diff --git a/Cargo.lock b/Cargo.lock
index ab6731e..c784246 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -106,7 +106,7 @@
  "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.60 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -1138,19 +1138,12 @@
 
 [[package]]
 name = "hashbrown"
-version = "0.4.0"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-alloc 1.0.0",
  "rustc-std-workspace-core 1.0.0",
-]
-
-[[package]]
-name = "hashbrown"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
  "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2736,7 +2729,7 @@
 
 [[package]]
 name = "rustc-demangle"
-version = "0.1.15"
+version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "compiler_builtins 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2894,7 +2887,7 @@
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "punycode 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
- "rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_data_structures 0.0.0",
  "rustc_metadata 0.0.0",
  "rustc_target 0.0.0",
@@ -3534,7 +3527,7 @@
  "core 0.0.0",
  "dlmalloc 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fortanix-sgx-abi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "hashbrown 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hashbrown 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.60 (registry+https://github.com/rust-lang/crates.io-index)",
  "panic_abort 0.0.0",
  "panic_unwind 0.0.0",
@@ -4450,7 +4443,6 @@
 "checksum globset 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ef4feaabe24a0a658fd9cf4a9acf6ed284f045c77df0f49020ba3245cfb7b454"
 "checksum h2 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)" = "a539b63339fbbb00e081e84b6e11bd1d9634a82d91da2984a18ac74a8823f392"
 "checksum handlebars 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "df044dd42cdb7e32f28557b661406fc0f2494be75199779998810dbc35030e0d"
-"checksum hashbrown 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9529213c67695ca2d146e6f263b7b72df8fa973368beadf767e8ed80c03f2f36"
 "checksum hashbrown 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e1de41fb8dba9714efd92241565cdff73f78508c95697dd56787d3cba27e2353"
 "checksum heck 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ea04fa3ead4e05e51a7c806fc07271fdbde4e246a6c6d1efd52e72230b771b82"
 "checksum hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
@@ -4600,7 +4592,7 @@
 "checksum rustc-ap-serialize 546.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "61673783f2089e01033ffa82d1988f55175402071b31253a358292e1624d4602"
 "checksum rustc-ap-syntax 546.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "28f3dd1346d5b0269c07a4a78855e309a298ab569c9c1302d4d4f57f8eee4e84"
 "checksum rustc-ap-syntax_pos 546.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "45e67b526dbda3a0c7dab91c8947d43685e7697f52686a4949da3c179cd7c979"
-"checksum rustc-demangle 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "a7f4dccf6f4891ebcc0c39f9b6eb1a83b9bf5d747cb439ec6fba4f3b977038af"
+"checksum rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
 "checksum rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7540fc8b0c49f096ee9c961cda096467dce8084bec6bdca2fc83895fd9b28cb8"
 "checksum rustc-rayon 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d2e07e19601f21c59aad953c2632172ba70cb27e685771514ea66e4062b3363"
 "checksum rustc-rayon-core 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "79d38ca7cbc22fa59f09d8534ea4b27f67b0facf0cbe274433aceea227a02543"
diff --git a/config.toml.example b/config.toml.example
index cb9f388..a3ec4f2 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -141,10 +141,10 @@
 # library and facade crates.
 #compiler-docs = false
 
-# Indicate whether submodules are managed and updated automatically.
+# Indicate whether git submodules are managed and updated automatically.
 #submodules = true
 
-# Update submodules only when the checked out commit in the submodules differs
+# Update git submodules only when the checked out commit in the submodules differs
 # from what is committed in the main rustc repo.
 #fast-submodules = true
 
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 9c01de8..ce92ce0 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -37,7 +37,7 @@
             let mut new = None;
             if let Some(current_as_str) = args[i].to_str() {
                 if (&*args[i - 1] == "-C" && current_as_str.starts_with("metadata")) ||
-                   current_as_str.starts_with("-Cmetadata") {
+                    current_as_str.starts_with("-Cmetadata") {
                     new = Some(format!("{}-{}", current_as_str, s));
                 }
             }
@@ -89,7 +89,7 @@
     if let Some(crate_name) = crate_name {
         if let Some(target) = env::var_os("RUSTC_TIME") {
             if target == "all" ||
-               target.into_string().unwrap().split(",").any(|c| c.trim() == crate_name)
+                target.into_string().unwrap().split(",").any(|c| c.trim() == crate_name)
             {
                 cmd.arg("-Ztime");
             }
@@ -102,8 +102,13 @@
     // FIXME: the fact that core here is excluded is due to core_arch from our stdarch submodule
     // being broken on the beta compiler with bootstrap passed, so this is a temporary workaround
     // (we've just snapped, so there are no cfg(bootstrap) related annotations in core).
-    if stage == "0" && crate_name != Some("core") {
-        cmd.arg("--cfg").arg("bootstrap");
+    if stage == "0" {
+        if crate_name != Some("core") {
+            cmd.arg("--cfg").arg("bootstrap");
+        } else {
+            // NOTE(eddyb) see FIXME above, except now we need annotations again in core.
+            cmd.arg("--cfg").arg("boostrap_stdarch_ignore_this");
+        }
     }
 
     // Print backtrace in case of ICE
@@ -276,10 +281,6 @@
                 cmd.arg("-C").arg("target-feature=-crt-static");
             }
         }
-
-        if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
-            cmd.arg("--remap-path-prefix").arg(&map);
-        }
     } else {
         // Override linker if necessary.
         if let Ok(host_linker) = env::var("RUSTC_HOST_LINKER") {
@@ -296,6 +297,10 @@
         }
     }
 
+    if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
+        cmd.arg("--remap-path-prefix").arg(&map);
+    }
+
     // Force all crates compiled by this compiler to (a) be unstable and (b)
     // allow the `rustc_private` feature to link to other unstable crates
     // also in the sysroot. We also do this for host crates, since those
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 8dad5f2..f0054c3 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -754,76 +754,20 @@
         let mut cargo = Command::new(&self.initial_cargo);
         let out_dir = self.stage_out(compiler, mode);
 
-        // command specific path, we call clear_if_dirty with this
-        let mut my_out = match cmd {
-            "build" => self.cargo_out(compiler, mode, target),
-
-            // This is the intended out directory for crate documentation.
-            "doc" | "rustdoc" =>  self.crate_doc_out(target),
-
-            _ => self.stage_out(compiler, mode),
-        };
-
-        // This is for the original compiler, but if we're forced to use stage 1, then
-        // std/test/rustc stamps won't exist in stage 2, so we need to get those from stage 1, since
-        // we copy the libs forward.
-        let cmp = self.compiler_for(compiler.stage, compiler.host, target);
-
-        let libstd_stamp = match cmd {
-            "check" | "clippy" | "fix" => check::libstd_stamp(self, cmp, target),
-            _ => compile::libstd_stamp(self, cmp, target),
-        };
-
-        let libtest_stamp = match cmd {
-            "check" | "clippy" | "fix" => check::libtest_stamp(self, cmp, target),
-            _ => compile::libtest_stamp(self, cmp, target),
-        };
-
-        let librustc_stamp = match cmd {
-            "check" | "clippy" | "fix" => check::librustc_stamp(self, cmp, target),
-            _ => compile::librustc_stamp(self, cmp, target),
-        };
+        // Codegen backends are not yet tracked by -Zbinary-dep-depinfo,
+        // so we need to explicitly clear out if they've been updated.
+        for backend in self.codegen_backends(compiler) {
+            self.clear_if_dirty(&out_dir, &backend);
+        }
 
         if cmd == "doc" || cmd == "rustdoc" {
-            if mode == Mode::Rustc || mode == Mode::ToolRustc || mode == Mode::Codegen {
+            let my_out = match mode {
                 // This is the intended out directory for compiler documentation.
-                my_out = self.compiler_doc_out(target);
-            }
+                Mode::Rustc | Mode::ToolRustc | Mode::Codegen => self.compiler_doc_out(target),
+                _ => self.crate_doc_out(target),
+            };
             let rustdoc = self.rustdoc(compiler);
             self.clear_if_dirty(&my_out, &rustdoc);
-        } else if cmd != "test" {
-            match mode {
-                Mode::Std => {
-                    self.clear_if_dirty(&my_out, &self.rustc(compiler));
-                    for backend in self.codegen_backends(compiler) {
-                        self.clear_if_dirty(&my_out, &backend);
-                    }
-                },
-                Mode::Test => {
-                    self.clear_if_dirty(&my_out, &libstd_stamp);
-                },
-                Mode::Rustc => {
-                    self.clear_if_dirty(&my_out, &self.rustc(compiler));
-                    self.clear_if_dirty(&my_out, &libstd_stamp);
-                    self.clear_if_dirty(&my_out, &libtest_stamp);
-                },
-                Mode::Codegen => {
-                    self.clear_if_dirty(&my_out, &librustc_stamp);
-                },
-                Mode::ToolBootstrap => { },
-                Mode::ToolStd => {
-                    self.clear_if_dirty(&my_out, &libstd_stamp);
-                },
-                Mode::ToolTest => {
-                    self.clear_if_dirty(&my_out, &libstd_stamp);
-                    self.clear_if_dirty(&my_out, &libtest_stamp);
-                },
-                Mode::ToolRustc => {
-                    self.clear_if_dirty(&my_out, &libstd_stamp);
-                    self.clear_if_dirty(&my_out, &libtest_stamp);
-                    self.clear_if_dirty(&my_out, &librustc_stamp);
-                },
-            }
         }
 
         cargo
@@ -861,6 +805,19 @@
             },
         }
 
+        // This tells Cargo (and in turn, rustc) to output more complete
+        // dependency information.  Most importantly for rustbuild, this
+        // includes sysroot artifacts, like libstd, which means that we don't
+        // need to track those in rustbuild (an error prone process!). This
+        // feature is currently unstable as there may be some bugs and such, but
+        // it represents a big improvement in rustbuild's reliability on
+        // rebuilds, so we're using it here.
+        //
+        // For some additional context, see #63470 (the PR originally adding
+        // this), as well as #63012 which is the tracking issue for this
+        // feature on the rustc side.
+        cargo.arg("-Zbinary-dep-depinfo");
+
         cargo.arg("-j").arg(self.jobs().to_string());
         // Remove make-related flags to ensure Cargo can correctly set things up
         cargo.env_remove("MAKEFLAGS");
diff --git a/src/bootstrap/cc_detect.rs b/src/bootstrap/cc_detect.rs
index c58a98b..a4cb81d3 100644
--- a/src/bootstrap/cc_detect.rs
+++ b/src/bootstrap/cc_detect.rs
@@ -46,7 +46,7 @@
     } else if target.contains("openbsd") {
         Some(PathBuf::from("ar"))
     } else if target.contains("vxworks") {
-        Some(PathBuf::from("vx-ar"))
+        Some(PathBuf::from("wr-ar"))
     } else {
         let parent = cc.parent().unwrap();
         let file = cc.file_name().unwrap().to_str().unwrap();
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index 11b082a..6e6fea6 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -245,7 +245,6 @@
         let libdir = builder.sysroot_libdir(compiler, target);
         let hostdir = builder.sysroot_libdir(compiler, compiler.host);
         add_to_sysroot(&builder, &libdir, &hostdir, &rustdoc_stamp(builder, compiler, target));
-        builder.cargo(compiler, Mode::ToolRustc, target, "clean");
     }
 }
 
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 4b4b072..96987d0 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -15,7 +15,7 @@
 use std::process::{Command, Stdio, exit};
 use std::str;
 
-use build_helper::{output, mtime, t, up_to_date};
+use build_helper::{output, t, up_to_date};
 use filetime::FileTime;
 use serde::Deserialize;
 use serde_json;
@@ -274,8 +274,6 @@
             // for reason why the sanitizers are not built in stage0.
             copy_apple_sanitizer_dylibs(builder, &builder.native_dir(target), "osx", &libdir);
         }
-
-        builder.cargo(target_compiler, Mode::ToolStd, target, "clean");
     }
 }
 
@@ -480,8 +478,6 @@
             &builder.sysroot_libdir(target_compiler, compiler.host),
             &libtest_stamp(builder, compiler, target)
         );
-
-        builder.cargo(target_compiler, Mode::ToolTest, target, "clean");
     }
 }
 
@@ -639,7 +635,6 @@
             &builder.sysroot_libdir(target_compiler, compiler.host),
             &librustc_stamp(builder, compiler, target)
         );
-        builder.cargo(target_compiler, Mode::ToolRustc, target, "clean");
     }
 }
 
@@ -795,6 +790,9 @@
             if builder.config.llvm_use_libcxx {
                 cargo.env("LLVM_USE_LIBCXX", "1");
             }
+            if builder.config.llvm_optimize && !builder.config.llvm_release_debuginfo {
+                cargo.env("LLVM_NDEBUG", "1");
+            }
         }
         _ => panic!("unknown backend: {}", backend),
     }
@@ -1202,41 +1200,13 @@
         deps.push((path_to_add.into(), false));
     }
 
-    // Now we want to update the contents of the stamp file, if necessary. First
-    // we read off the previous contents along with its mtime. If our new
-    // contents (the list of files to copy) is different or if any dep's mtime
-    // is newer then we rewrite the stamp file.
     deps.sort();
-    let stamp_contents = fs::read(stamp);
-    let stamp_mtime = mtime(&stamp);
     let mut new_contents = Vec::new();
-    let mut max = None;
-    let mut max_path = None;
     for (dep, proc_macro) in deps.iter() {
-        let mtime = mtime(dep);
-        if Some(mtime) > max {
-            max = Some(mtime);
-            max_path = Some(dep.clone());
-        }
         new_contents.extend(if *proc_macro { b"h" } else { b"t" });
         new_contents.extend(dep.to_str().unwrap().as_bytes());
         new_contents.extend(b"\0");
     }
-    let max = max.unwrap();
-    let max_path = max_path.unwrap();
-    let contents_equal = stamp_contents
-        .map(|contents| contents == new_contents)
-        .unwrap_or_default();
-    if contents_equal && max <= stamp_mtime {
-        builder.verbose(&format!("not updating {:?}; contents equal and {:?} <= {:?}",
-                stamp, max, stamp_mtime));
-        return deps.into_iter().map(|(d, _)| d).collect()
-    }
-    if max > stamp_mtime {
-        builder.verbose(&format!("updating {:?} as {:?} changed", stamp, max_path));
-    } else {
-        builder.verbose(&format!("updating {:?} as deps changed", stamp));
-    }
     t!(fs::write(&stamp, &new_contents));
     deps.into_iter().map(|(d, _)| d).collect()
 }
diff --git a/src/bootstrap/mk/Makefile.in b/src/bootstrap/mk/Makefile.in
index 73d6fe5..e0a1f46 100644
--- a/src/bootstrap/mk/Makefile.in
+++ b/src/bootstrap/mk/Makefile.in
@@ -81,5 +81,14 @@
 ci-subset-2:
 	$(Q)$(BOOTSTRAP) test $(TESTS_IN_2)
 
+TESTS_IN_MINGW_2 := \
+	src/test/ui \
+	src/test/compile-fail
+
+ci-mingw-subset-1:
+	$(Q)$(BOOTSTRAP) test $(TESTS_IN_MINGW_2:%=--exclude %)
+ci-mingw-subset-2:
+	$(Q)$(BOOTSTRAP) test $(TESTS_IN_MINGW_2)
+
 
 .PHONY: dist
diff --git a/src/bootstrap/sanity.rs b/src/bootstrap/sanity.rs
index 4e3930c..bffe748 100644
--- a/src/bootstrap/sanity.rs
+++ b/src/bootstrap/sanity.rs
@@ -202,10 +202,6 @@
                         panic!("couldn't find libc.a in musl dir: {}",
                                root.join("lib").display());
                     }
-                    if fs::metadata(root.join("lib/libunwind.a")).is_err() {
-                        panic!("couldn't find libunwind.a in musl dir: {}",
-                               root.join("lib").display());
-                    }
                 }
                 None => {
                     panic!("when targeting MUSL either the rust.musl-root \
diff --git a/src/ci/azure-pipelines/auto.yml b/src/ci/azure-pipelines/auto.yml
index 06fa3bd..77c9cda 100644
--- a/src/ci/azure-pipelines/auto.yml
+++ b/src/ci/azure-pipelines/auto.yml
@@ -272,7 +272,7 @@
       i686-mingw-1:
         MSYS_BITS: 32
         RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
-        SCRIPT: make ci-subset-1
+        SCRIPT: make ci-mingw-subset-1
         MINGW_URL: https://rust-lang-ci-mirrors.s3-us-west-1.amazonaws.com/rustc
         MINGW_ARCHIVE: i686-6.3.0-release-posix-dwarf-rt_v5-rev2.7z
         MINGW_DIR: mingw32
@@ -282,13 +282,13 @@
       i686-mingw-2:
         MSYS_BITS: 32
         RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
-        SCRIPT: make ci-subset-2
+        SCRIPT: make ci-mingw-subset-2
         MINGW_URL: https://rust-lang-ci-mirrors.s3-us-west-1.amazonaws.com/rustc
         MINGW_ARCHIVE: i686-6.3.0-release-posix-dwarf-rt_v5-rev2.7z
         MINGW_DIR: mingw32
       x86_64-mingw-1:
         MSYS_BITS: 64
-        SCRIPT: make ci-subset-1
+        SCRIPT: make ci-mingw-subset-1
         RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu
         MINGW_URL: https://rust-lang-ci-mirrors.s3-us-west-1.amazonaws.com/rustc
         MINGW_ARCHIVE: x86_64-6.3.0-release-posix-seh-rt_v5-rev2.7z
@@ -298,7 +298,7 @@
         NO_LLVM_ASSERTIONS: 1
       x86_64-mingw-2:
         MSYS_BITS: 64
-        SCRIPT: make ci-subset-2
+        SCRIPT: make ci-mingw-subset-2
         RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu
         MINGW_URL: https://rust-lang-ci-mirrors.s3-us-west-1.amazonaws.com/rustc
         MINGW_ARCHIVE: x86_64-6.3.0-release-posix-seh-rt_v5-rev2.7z
diff --git a/src/ci/azure-pipelines/steps/run.yml b/src/ci/azure-pipelines/steps/run.yml
index ca32888..ac6b344 100644
--- a/src/ci/azure-pipelines/steps/run.yml
+++ b/src/ci/azure-pipelines/steps/run.yml
@@ -199,7 +199,7 @@
 # Upload CPU usage statistics that we've been gathering this whole time. Always
 # execute this step in case we want to inspect failed builds, but don't let
 # errors here ever fail the build since this is just informational.
-- bash: aws s3 cp --acl public-read cpu-usage.csv s3://$DEPLOY_BUCKET/rustc-builds/$BUILD_SOURCEVERSION/cpu-$SYSTEM_JOBNAME.csv
+- bash: aws s3 cp --acl public-read cpu-usage.csv s3://$DEPLOY_BUCKET/rustc-builds/$BUILD_SOURCEVERSION/cpu-$CI_JOB_NAME.csv
   env:
     AWS_SECRET_ACCESS_KEY: $(AWS_SECRET_ACCESS_KEY)
   condition: variables['AWS_SECRET_ACCESS_KEY']
diff --git a/src/ci/docker/scripts/musl-toolchain.sh b/src/ci/docker/scripts/musl-toolchain.sh
index 55899fa..74ba2f0 100644
--- a/src/ci/docker/scripts/musl-toolchain.sh
+++ b/src/ci/docker/scripts/musl-toolchain.sh
@@ -54,29 +54,3 @@
         ln -s $TARGET-g++ /usr/local/bin/$exec
     done
 fi
-
-export CC=$TARGET-gcc
-export CXX=$TARGET-g++
-
-LLVM=70
-
-# may have been downloaded in a previous run
-if [ ! -d libunwind-release_$LLVM ]; then
-  curl -L https://github.com/llvm-mirror/llvm/archive/release_$LLVM.tar.gz | tar xzf -
-  curl -L https://github.com/llvm-mirror/libunwind/archive/release_$LLVM.tar.gz | tar xzf -
-fi
-
-# fixme(mati865): Replace it with https://github.com/rust-lang/rust/pull/59089
-mkdir libunwind-build
-cd libunwind-build
-cmake ../libunwind-release_$LLVM \
-          -DLLVM_PATH=/build/llvm-release_$LLVM \
-          -DLIBUNWIND_ENABLE_SHARED=0 \
-          -DCMAKE_C_COMPILER=$CC \
-          -DCMAKE_CXX_COMPILER=$CXX \
-          -DCMAKE_C_FLAGS="$CFLAGS" \
-          -DCMAKE_CXX_FLAGS="$CXXFLAGS"
-
-hide_output make -j$(nproc)
-cp lib/libunwind.a $OUTPUT/$TARGET/lib
-cd - && rm -rf libunwind-build
diff --git a/src/ci/docker/scripts/musl.sh b/src/ci/docker/scripts/musl.sh
index c2cf77d..d847c40 100644
--- a/src/ci/docker/scripts/musl.sh
+++ b/src/ci/docker/scripts/musl.sh
@@ -20,6 +20,8 @@
 TAG=$1
 shift
 
+# Ancient binutils versions don't understand debug symbols produced by more recent tools.
+# Apparently applying `-fPIC` everywhere allows them to link successfully.
 export CFLAGS="-fPIC $CFLAGS"
 
 MUSL=musl-1.1.22
@@ -38,27 +40,3 @@
 fi
 hide_output make install
 hide_output make clean
-
-cd ..
-
-LLVM=70
-
-# may have been downloaded in a previous run
-if [ ! -d libunwind-release_$LLVM ]; then
-  curl -L https://github.com/llvm-mirror/llvm/archive/release_$LLVM.tar.gz | tar xzf -
-  curl -L https://github.com/llvm-mirror/libunwind/archive/release_$LLVM.tar.gz | tar xzf -
-fi
-
-mkdir libunwind-build
-cd libunwind-build
-cmake ../libunwind-release_$LLVM \
-          -DLLVM_PATH=/build/llvm-release_$LLVM \
-          -DLIBUNWIND_ENABLE_SHARED=0 \
-          -DCMAKE_C_COMPILER=$CC \
-          -DCMAKE_CXX_COMPILER=$CXX \
-          -DCMAKE_C_FLAGS="$CFLAGS" \
-          -DCMAKE_CXX_FLAGS="$CXXFLAGS"
-
-hide_output make -j$(nproc)
-cp lib/libunwind.a /musl-$TAG/lib
-cd ../ && rm -rf libunwind-build
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index c92db51..c61e318 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -91,8 +91,10 @@
     CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState
 };
 use core::ptr::{self, NonNull, Unique};
+use core::slice;
 use core::task::{Context, Poll};
 
+use crate::alloc::{self, Global, Alloc};
 use crate::vec::Vec;
 use crate::raw_vec::RawVec;
 use crate::str::from_boxed_utf8_unchecked;
@@ -121,6 +123,34 @@
         box x
     }
 
+    /// Constructs a new box with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut five = Box::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit() -> Box<mem::MaybeUninit<T>> {
+        let layout = alloc::Layout::new::<mem::MaybeUninit<T>>();
+        let ptr = unsafe {
+            Global.alloc(layout)
+                .unwrap_or_else(|_| alloc::handle_alloc_error(layout))
+        };
+        Box(ptr.cast().into())
+    }
+
     /// Constructs a new `Pin<Box<T>>`. If `T` does not implement `Unpin`, then
     /// `x` will be pinned in memory and unable to be moved.
     #[stable(feature = "pin", since = "1.33.0")]
@@ -130,6 +160,111 @@
     }
 }
 
+impl<T> Box<[T]> {
+    /// Constructs a new boxed slice with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
+        let layout = alloc::Layout::array::<mem::MaybeUninit<T>>(len).unwrap();
+        let ptr = unsafe { alloc::alloc(layout) };
+        let unique = Unique::new(ptr).unwrap_or_else(|| alloc::handle_alloc_error(layout));
+        let slice = unsafe { slice::from_raw_parts_mut(unique.cast().as_ptr(), len) };
+        Box(Unique::from(slice))
+    }
+}
+
+impl<T> Box<mem::MaybeUninit<T>> {
+    /// Converts to `Box<T>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut five = Box::<u32>::new_uninit();
+    ///
+    /// let five: Box<u32> = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Box<T> {
+        Box(Box::into_unique(self).cast())
+    }
+}
+
+impl<T> Box<[mem::MaybeUninit<T>]> {
+    /// Converts to `Box<[T]>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the values
+    /// really are in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Box<[T]> {
+        Box(Unique::new_unchecked(Box::into_raw(self) as _))
+    }
+}
+
 impl<T: ?Sized> Box<T> {
     /// Constructs a box from a raw pointer.
     ///
diff --git a/src/liballoc/collections/mod.rs b/src/liballoc/collections/mod.rs
index 5a33ddc..f1f22fe 100644
--- a/src/liballoc/collections/mod.rs
+++ b/src/liballoc/collections/mod.rs
@@ -41,32 +41,35 @@
 #[doc(no_inline)]
 pub use vec_deque::VecDeque;
 
-use crate::alloc::{AllocErr, LayoutErr};
+use crate::alloc::{Layout, LayoutErr};
 
-/// Augments `AllocErr` with a CapacityOverflow variant.
+/// The error type for `try_reserve` methods.
 #[derive(Clone, PartialEq, Eq, Debug)]
 #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-pub enum CollectionAllocErr {
+pub enum TryReserveError {
     /// Error due to the computed capacity exceeding the collection's maximum
     /// (usually `isize::MAX` bytes).
     CapacityOverflow,
-    /// Error due to the allocator (see the `AllocErr` type's docs).
-    AllocErr,
+
+    /// The memory allocator returned an error
+    AllocError {
+        /// The layout of allocation request that failed
+        layout: Layout,
+
+        #[doc(hidden)]
+        #[unstable(feature = "container_error_extra", issue = "0", reason = "\
+            Enable exposing the allocator’s custom error value \
+            if an associated type is added in the future: \
+            https://github.com/rust-lang/wg-allocators/issues/23")]
+        non_exhaustive: (),
+    },
 }
 
 #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-impl From<AllocErr> for CollectionAllocErr {
-    #[inline]
-    fn from(AllocErr: AllocErr) -> Self {
-        CollectionAllocErr::AllocErr
-    }
-}
-
-#[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-impl From<LayoutErr> for CollectionAllocErr {
+impl From<LayoutErr> for TryReserveError {
     #[inline]
     fn from(_: LayoutErr) -> Self {
-        CollectionAllocErr::CapacityOverflow
+        TryReserveError::CapacityOverflow
     }
 }
 
diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index 9240346..2fc8741 100644
--- a/src/liballoc/collections/vec_deque.rs
+++ b/src/liballoc/collections/vec_deque.rs
@@ -18,7 +18,7 @@
 use core::slice;
 use core::hash::{Hash, Hasher};
 
-use crate::collections::CollectionAllocErr;
+use crate::collections::TryReserveError;
 use crate::raw_vec::RawVec;
 use crate::vec::Vec;
 
@@ -576,10 +576,10 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     /// use std::collections::VecDeque;
     ///
-    /// fn process_data(data: &[u32]) -> Result<VecDeque<u32>, CollectionAllocErr> {
+    /// fn process_data(data: &[u32]) -> Result<VecDeque<u32>, TryReserveError> {
     ///     let mut output = VecDeque::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -595,7 +595,7 @@
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), CollectionAllocErr>  {
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError>  {
         self.try_reserve(additional)
     }
 
@@ -614,10 +614,10 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     /// use std::collections::VecDeque;
     ///
-    /// fn process_data(data: &[u32]) -> Result<VecDeque<u32>, CollectionAllocErr> {
+    /// fn process_data(data: &[u32]) -> Result<VecDeque<u32>, TryReserveError> {
     ///     let mut output = VecDeque::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -633,12 +633,12 @@
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> {
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         let old_cap = self.cap();
         let used_cap = self.len() + 1;
         let new_cap = used_cap.checked_add(additional)
             .and_then(|needed_cap| needed_cap.checked_next_power_of_two())
-            .ok_or(CollectionAllocErr::CapacityOverflow)?;
+            .ok_or(TryReserveError::CapacityOverflow)?;
 
         if new_cap > old_cap {
             self.buf.try_reserve_exact(used_cap, new_cap - used_cap)?;
diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index 7421bed..4a48945 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -87,6 +87,7 @@
 #![feature(const_in_array_repeat_expressions)]
 #![feature(dispatch_from_dyn)]
 #![feature(core_intrinsics)]
+#![feature(container_error_extra)]
 #![feature(dropck_eyepatch)]
 #![feature(exact_size_is_empty)]
 #![feature(fmt_internals)]
diff --git a/src/liballoc/macros.rs b/src/liballoc/macros.rs
index 250c419..0b5e186d 100644
--- a/src/liballoc/macros.rs
+++ b/src/liballoc/macros.rs
@@ -98,5 +98,5 @@
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! format {
-    ($($arg:tt)*) => ($crate::fmt::format(format_args!($($arg)*)))
+    ($($arg:tt)*) => ($crate::fmt::format(::core::format_args!($($arg)*)))
 }
diff --git a/src/liballoc/raw_vec.rs b/src/liballoc/raw_vec.rs
index 0abab45..bc8a38f 100644
--- a/src/liballoc/raw_vec.rs
+++ b/src/liballoc/raw_vec.rs
@@ -7,8 +7,8 @@
 use core::ptr::{self, NonNull, Unique};
 use core::slice;
 
-use crate::alloc::{Alloc, Layout, Global, handle_alloc_error};
-use crate::collections::CollectionAllocErr::{self, *};
+use crate::alloc::{Alloc, Layout, Global, AllocErr, handle_alloc_error};
+use crate::collections::TryReserveError::{self, *};
 use crate::boxed::Box;
 
 #[cfg(test)]
@@ -385,7 +385,7 @@
 
     /// The same as `reserve_exact`, but returns on errors instead of panicking or aborting.
     pub fn try_reserve_exact(&mut self, used_capacity: usize, needed_extra_capacity: usize)
-           -> Result<(), CollectionAllocErr> {
+           -> Result<(), TryReserveError> {
 
         self.reserve_internal(used_capacity, needed_extra_capacity, Fallible, Exact)
     }
@@ -413,7 +413,7 @@
     pub fn reserve_exact(&mut self, used_capacity: usize, needed_extra_capacity: usize) {
         match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Exact) {
             Err(CapacityOverflow) => capacity_overflow(),
-            Err(AllocErr) => unreachable!(),
+            Err(AllocError { .. }) => unreachable!(),
             Ok(()) => { /* yay */ }
          }
      }
@@ -422,7 +422,7 @@
     /// needed_extra_capacity` elements. This logic is used in amortized reserve methods.
     /// Returns `(new_capacity, new_alloc_size)`.
     fn amortized_new_size(&self, used_capacity: usize, needed_extra_capacity: usize)
-        -> Result<usize, CollectionAllocErr> {
+        -> Result<usize, TryReserveError> {
 
         // Nothing we can really do about these checks :(
         let required_cap = used_capacity.checked_add(needed_extra_capacity)
@@ -435,7 +435,7 @@
 
     /// The same as `reserve`, but returns on errors instead of panicking or aborting.
     pub fn try_reserve(&mut self, used_capacity: usize, needed_extra_capacity: usize)
-        -> Result<(), CollectionAllocErr> {
+        -> Result<(), TryReserveError> {
         self.reserve_internal(used_capacity, needed_extra_capacity, Fallible, Amortized)
     }
 
@@ -494,7 +494,7 @@
     pub fn reserve(&mut self, used_capacity: usize, needed_extra_capacity: usize) {
         match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Amortized) {
             Err(CapacityOverflow) => capacity_overflow(),
-            Err(AllocErr) => unreachable!(),
+            Err(AllocError { .. }) => unreachable!(),
             Ok(()) => { /* yay */ }
         }
     }
@@ -640,10 +640,8 @@
         needed_extra_capacity: usize,
         fallibility: Fallibility,
         strategy: ReserveStrategy,
-    ) -> Result<(), CollectionAllocErr> {
+    ) -> Result<(), TryReserveError> {
         unsafe {
-            use crate::alloc::AllocErr;
-
             // NOTE: we don't early branch on ZSTs here because we want this
             // to actually catch "asking for more than usize::MAX" in that case.
             // If we make it past the first branch then we are guaranteed to
@@ -672,12 +670,16 @@
                 None => self.a.alloc(new_layout),
             };
 
-            match (&res, fallibility) {
+            let ptr = match (res, fallibility) {
                 (Err(AllocErr), Infallible) => handle_alloc_error(new_layout),
-                _ => {}
-            }
+                (Err(AllocErr), Fallible) => return Err(TryReserveError::AllocError {
+                    layout: new_layout,
+                    non_exhaustive: (),
+                }),
+                (Ok(ptr), _) => ptr,
+            };
 
-            self.ptr = res?.cast().into();
+            self.ptr = ptr.cast().into();
             self.cap = new_cap;
 
             Ok(())
@@ -737,7 +739,7 @@
 // all 4GB in user-space. e.g., PAE or x32
 
 #[inline]
-fn alloc_guard(alloc_size: usize) -> Result<(), CollectionAllocErr> {
+fn alloc_guard(alloc_size: usize) -> Result<(), TryReserveError> {
     if mem::size_of::<usize>() < 8 && alloc_size > core::isize::MAX as usize {
         Err(CapacityOverflow)
     } else {
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 0c406a9..2b222ca 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -327,6 +327,37 @@
         }))
     }
 
+    /// Constructs a new `Rc` with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let mut five = Rc::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     Rc::get_mut_unchecked(&mut five).as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit() -> Rc<mem::MaybeUninit<T>> {
+        unsafe {
+            Rc::from_ptr(Rc::allocate_for_layout(
+                Layout::new::<T>(),
+                |mem| mem as *mut RcBox<mem::MaybeUninit<T>>,
+            ))
+        }
+    }
+
     /// Constructs a new `Pin<Rc<T>>`. If `T` does not implement `Unpin`, then
     /// `value` will be pinned in memory and unable to be moved.
     #[stable(feature = "pin", since = "1.33.0")]
@@ -377,6 +408,118 @@
     }
 }
 
+impl<T> Rc<[T]> {
+    /// Constructs a new reference-counted slice with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let mut values = Rc::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     Rc::get_mut_unchecked(&mut values)[0].as_mut_ptr().write(1);
+    ///     Rc::get_mut_unchecked(&mut values)[1].as_mut_ptr().write(2);
+    ///     Rc::get_mut_unchecked(&mut values)[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
+        unsafe {
+            Rc::from_ptr(Rc::allocate_for_slice(len))
+        }
+    }
+}
+
+impl<T> Rc<mem::MaybeUninit<T>> {
+    /// Converts to `Rc<T>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let mut five = Rc::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     Rc::get_mut_unchecked(&mut five).as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Rc<T> {
+        Rc::from_inner(mem::ManuallyDrop::new(self).ptr.cast())
+    }
+}
+
+impl<T> Rc<[mem::MaybeUninit<T>]> {
+    /// Converts to `Rc<[T]>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let mut values = Rc::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     Rc::get_mut_unchecked(&mut values)[0].as_mut_ptr().write(1);
+    ///     Rc::get_mut_unchecked(&mut values)[1].as_mut_ptr().write(2);
+    ///     Rc::get_mut_unchecked(&mut values)[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Rc<[T]> {
+        Rc::from_ptr(mem::ManuallyDrop::new(self).ptr.as_ptr() as _)
+    }
+}
+
 impl<T: ?Sized> Rc<T> {
     /// Consumes the `Rc`, returning the wrapped pointer.
     ///
@@ -560,13 +703,46 @@
     pub fn get_mut(this: &mut Self) -> Option<&mut T> {
         if Rc::is_unique(this) {
             unsafe {
-                Some(&mut this.ptr.as_mut().value)
+                Some(Rc::get_mut_unchecked(this))
             }
         } else {
             None
         }
     }
 
+    /// Returns a mutable reference to the inner value,
+    /// without any check.
+    ///
+    /// See also [`get_mut`], which is safe and does appropriate checks.
+    ///
+    /// [`get_mut`]: struct.Rc.html#method.get_mut
+    ///
+    /// # Safety
+    ///
+    /// Any other `Rc` or [`Weak`] pointers to the same value must not be dereferenced
+    /// for the duration of the returned borrow.
+    /// This is trivially the case if no such pointers exist,
+    /// for example immediately after `Rc::new`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let mut x = Rc::new(String::new());
+    /// unsafe {
+    ///     Rc::get_mut_unchecked(&mut x).push_str("foo")
+    /// }
+    /// assert_eq!(*x, "foo");
+    /// ```
+    #[inline]
+    #[unstable(feature = "get_mut_unchecked", issue = "63292")]
+    pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {
+        &mut this.ptr.as_mut().value
+    }
+
     #[inline]
     #[stable(feature = "ptr_eq", since = "1.17.0")]
     /// Returns `true` if the two `Rc`s point to the same value (not
@@ -704,11 +880,11 @@
 
 impl<T: ?Sized> Rc<T> {
     /// Allocates an `RcBox<T>` with sufficient space for
-    /// an unsized value where the value has the layout provided.
+    /// a possibly-unsized value where the value has the layout provided.
     ///
     /// The function `mem_to_rcbox` is called with the data pointer
     /// and must return back a (potentially fat)-pointer for the `RcBox<T>`.
-    unsafe fn allocate_for_unsized(
+    unsafe fn allocate_for_layout(
         value_layout: Layout,
         mem_to_rcbox: impl FnOnce(*mut u8) -> *mut RcBox<T>
     ) -> *mut RcBox<T> {
@@ -737,7 +913,7 @@
     /// Allocates an `RcBox<T>` with sufficient space for an unsized value
     unsafe fn allocate_for_ptr(ptr: *const T) -> *mut RcBox<T> {
         // Allocate for the `RcBox<T>` using the given value.
-        Self::allocate_for_unsized(
+        Self::allocate_for_layout(
             Layout::for_value(&*ptr),
             |mem| set_data_ptr(ptr as *mut T, mem) as *mut RcBox<T>,
         )
@@ -768,7 +944,7 @@
 impl<T> Rc<[T]> {
     /// Allocates an `RcBox<[T]>` with the given length.
     unsafe fn allocate_for_slice(len: usize) -> *mut RcBox<[T]> {
-        Self::allocate_for_unsized(
+        Self::allocate_for_layout(
             Layout::array::<T>(len).unwrap(),
             |mem| ptr::slice_from_raw_parts_mut(mem as *mut T, len) as *mut RcBox<[T]>,
         )
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index eca726c..b65f191 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -56,7 +56,7 @@
 use core::str::{pattern::Pattern, lossy};
 
 use crate::borrow::{Cow, ToOwned};
-use crate::collections::CollectionAllocErr;
+use crate::collections::TryReserveError;
 use crate::boxed::Box;
 use crate::str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars};
 use crate::vec::Vec;
@@ -937,9 +937,9 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     ///
-    /// fn process_data(data: &str) -> Result<String, CollectionAllocErr> {
+    /// fn process_data(data: &str) -> Result<String, TryReserveError> {
     ///     let mut output = String::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -953,7 +953,7 @@
     /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> {
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.vec.try_reserve(additional)
     }
 
@@ -975,9 +975,9 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     ///
-    /// fn process_data(data: &str) -> Result<String, CollectionAllocErr> {
+    /// fn process_data(data: &str) -> Result<String, TryReserveError> {
     ///     let mut output = String::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -991,7 +991,7 @@
     /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), CollectionAllocErr>  {
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError>  {
         self.vec.try_reserve_exact(additional)
     }
 
diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 7d3b265..3411721 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -311,6 +311,37 @@
         Self::from_inner(Box::into_raw_non_null(x))
     }
 
+    /// Constructs a new `Arc` with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let mut five = Arc::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     Arc::get_mut_unchecked(&mut five).as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit() -> Arc<mem::MaybeUninit<T>> {
+        unsafe {
+            Arc::from_ptr(Arc::allocate_for_layout(
+                Layout::new::<T>(),
+                |mem| mem as *mut ArcInner<mem::MaybeUninit<T>>,
+            ))
+        }
+    }
+
     /// Constructs a new `Pin<Arc<T>>`. If `T` does not implement `Unpin`, then
     /// `data` will be pinned in memory and unable to be moved.
     #[stable(feature = "pin", since = "1.33.0")]
@@ -361,6 +392,118 @@
     }
 }
 
+impl<T> Arc<[T]> {
+    /// Constructs a new reference-counted slice with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let mut values = Arc::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     Arc::get_mut_unchecked(&mut values)[0].as_mut_ptr().write(1);
+    ///     Arc::get_mut_unchecked(&mut values)[1].as_mut_ptr().write(2);
+    ///     Arc::get_mut_unchecked(&mut values)[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    pub fn new_uninit_slice(len: usize) -> Arc<[mem::MaybeUninit<T>]> {
+        unsafe {
+            Arc::from_ptr(Arc::allocate_for_slice(len))
+        }
+    }
+}
+
+impl<T> Arc<mem::MaybeUninit<T>> {
+    /// Converts to `Arc<T>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let mut five = Arc::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     Arc::get_mut_unchecked(&mut five).as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Arc<T> {
+        Arc::from_inner(mem::ManuallyDrop::new(self).ptr.cast())
+    }
+}
+
+impl<T> Arc<[mem::MaybeUninit<T>]> {
+    /// Converts to `Arc<[T]>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: ../../std/mem/union.MaybeUninit.html#method.assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let mut values = Arc::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     Arc::get_mut_unchecked(&mut values)[0].as_mut_ptr().write(1);
+    ///     Arc::get_mut_unchecked(&mut values)[1].as_mut_ptr().write(2);
+    ///     Arc::get_mut_unchecked(&mut values)[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Arc<[T]> {
+        Arc::from_ptr(mem::ManuallyDrop::new(self).ptr.as_ptr() as _)
+    }
+}
+
 impl<T: ?Sized> Arc<T> {
     /// Consumes the `Arc`, returning the wrapped pointer.
     ///
@@ -593,11 +736,11 @@
 
 impl<T: ?Sized> Arc<T> {
     /// Allocates an `ArcInner<T>` with sufficient space for
-    /// an unsized value where the value has the layout provided.
+    /// a possibly-unsized value where the value has the layout provided.
     ///
     /// The function `mem_to_arcinner` is called with the data pointer
     /// and must return back a (potentially fat)-pointer for the `ArcInner<T>`.
-    unsafe fn allocate_for_unsized(
+    unsafe fn allocate_for_layout(
         value_layout: Layout,
         mem_to_arcinner: impl FnOnce(*mut u8) -> *mut ArcInner<T>
     ) -> *mut ArcInner<T> {
@@ -625,7 +768,7 @@
     /// Allocates an `ArcInner<T>` with sufficient space for an unsized value.
     unsafe fn allocate_for_ptr(ptr: *const T) -> *mut ArcInner<T> {
         // Allocate for the `ArcInner<T>` using the given value.
-        Self::allocate_for_unsized(
+        Self::allocate_for_layout(
             Layout::for_value(&*ptr),
             |mem| set_data_ptr(ptr as *mut T, mem) as *mut ArcInner<T>,
         )
@@ -656,7 +799,7 @@
 impl<T> Arc<[T]> {
     /// Allocates an `ArcInner<[T]>` with the given length.
     unsafe fn allocate_for_slice(len: usize) -> *mut ArcInner<[T]> {
-        Self::allocate_for_unsized(
+        Self::allocate_for_layout(
             Layout::array::<T>(len).unwrap(),
             |mem| ptr::slice_from_raw_parts_mut(mem as *mut T, len) as *mut ArcInner<[T]>,
         )
@@ -945,13 +1088,46 @@
             // the Arc itself to be `mut`, so we're returning the only possible
             // reference to the inner data.
             unsafe {
-                Some(&mut this.ptr.as_mut().data)
+                Some(Arc::get_mut_unchecked(this))
             }
         } else {
             None
         }
     }
 
+    /// Returns a mutable reference to the inner value,
+    /// without any check.
+    ///
+    /// See also [`get_mut`], which is safe and does appropriate checks.
+    ///
+    /// [`get_mut`]: struct.Arc.html#method.get_mut
+    ///
+    /// # Safety
+    ///
+    /// Any other `Arc` or [`Weak`] pointers to the same value must not be dereferenced
+    /// for the duration of the returned borrow.
+    /// This is trivially the case if no such pointers exist,
+    /// for example immediately after `Arc::new`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let mut x = Arc::new(String::new());
+    /// unsafe {
+    ///     Arc::get_mut_unchecked(&mut x).push_str("foo")
+    /// }
+    /// assert_eq!(*x, "foo");
+    /// ```
+    #[inline]
+    #[unstable(feature = "get_mut_unchecked", issue = "63292")]
+    pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {
+        &mut this.ptr.as_mut().data
+    }
+
     /// Determine whether this is the unique reference (including weak refs) to
     /// the underlying data.
     ///
diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs
index 765210e..55edf56 100644
--- a/src/liballoc/tests/string.rs
+++ b/src/liballoc/tests/string.rs
@@ -1,5 +1,5 @@
 use std::borrow::Cow;
-use std::collections::CollectionAllocErr::*;
+use std::collections::TryReserveError::*;
 use std::mem::size_of;
 use std::{usize, isize};
 
@@ -566,11 +566,11 @@
             } else { panic!("usize::MAX should trigger an overflow!") }
         } else {
             // Check isize::MAX + 1 is an OOM
-            if let Err(AllocErr) = empty_string.try_reserve(MAX_CAP + 1) {
+            if let Err(AllocError { .. }) = empty_string.try_reserve(MAX_CAP + 1) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
 
             // Check usize::MAX is an OOM
-            if let Err(AllocErr) = empty_string.try_reserve(MAX_USIZE) {
+            if let Err(AllocError { .. }) = empty_string.try_reserve(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an OOM!") }
         }
     }
@@ -590,7 +590,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         // Should always overflow in the add-to-len
@@ -629,10 +629,10 @@
             if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an overflow!") }
         } else {
-            if let Err(AllocErr) = empty_string.try_reserve_exact(MAX_CAP + 1) {
+            if let Err(AllocError { .. }) = empty_string.try_reserve_exact(MAX_CAP + 1) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
 
-            if let Err(AllocErr) = empty_string.try_reserve_exact(MAX_USIZE) {
+            if let Err(AllocError { .. }) = empty_string.try_reserve_exact(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an OOM!") }
         }
     }
@@ -651,7 +651,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs
index 6e8ffe1..29a22aa 100644
--- a/src/liballoc/tests/vec.rs
+++ b/src/liballoc/tests/vec.rs
@@ -2,7 +2,7 @@
 use std::mem::size_of;
 use std::{usize, isize};
 use std::vec::{Drain, IntoIter};
-use std::collections::CollectionAllocErr::*;
+use std::collections::TryReserveError::*;
 
 struct DropCounter<'a> {
     count: &'a mut u32,
@@ -1121,11 +1121,11 @@
             } else { panic!("usize::MAX should trigger an overflow!") }
         } else {
             // Check isize::MAX + 1 is an OOM
-            if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP + 1) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_CAP + 1) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
 
             // Check usize::MAX is an OOM
-            if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an OOM!") }
         }
     }
@@ -1145,7 +1145,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         // Should always overflow in the add-to-len
@@ -1168,7 +1168,7 @@
             if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
+            if let Err(AllocError { .. }) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         // Should fail in the mul-by-size
@@ -1209,10 +1209,10 @@
             if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an overflow!") }
         } else {
-            if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
 
-            if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_USIZE) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_USIZE) {
             } else { panic!("usize::MAX should trigger an OOM!") }
         }
     }
@@ -1231,7 +1231,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
@@ -1252,7 +1252,7 @@
             if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
+            if let Err(AllocError { .. }) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) {
diff --git a/src/liballoc/tests/vec_deque.rs b/src/liballoc/tests/vec_deque.rs
index 1bbcca9..d49b553 100644
--- a/src/liballoc/tests/vec_deque.rs
+++ b/src/liballoc/tests/vec_deque.rs
@@ -1,6 +1,6 @@
 use std::fmt::Debug;
 use std::collections::{VecDeque, vec_deque::Drain};
-use std::collections::CollectionAllocErr::*;
+use std::collections::TryReserveError::*;
 use std::mem::size_of;
 use std::{usize, isize};
 
@@ -1168,7 +1168,7 @@
             // VecDeque starts with capacity 7, always adds 1 to the capacity
             // and also rounds the number to next power of 2 so this is the
             // furthest we can go without triggering CapacityOverflow
-            if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_CAP) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
     }
@@ -1188,7 +1188,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         // Should always overflow in the add-to-len
@@ -1211,7 +1211,7 @@
             if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
+            if let Err(AllocError { .. }) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         // Should fail in the mul-by-size
@@ -1256,7 +1256,7 @@
             // VecDeque starts with capacity 7, always adds 1 to the capacity
             // and also rounds the number to next power of 2 so this is the
             // furthest we can go without triggering CapacityOverflow
-            if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP) {
+            if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_CAP) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
     }
@@ -1275,7 +1275,7 @@
             if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
+            if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
@@ -1296,7 +1296,7 @@
             if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an overflow!"); }
         } else {
-            if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
+            if let Err(AllocError { .. }) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
             } else { panic!("isize::MAX + 1 should trigger an OOM!") }
         }
         if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) {
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index dac04e4..d279895 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -70,7 +70,7 @@
 use core::slice::{self, SliceIndex};
 
 use crate::borrow::{ToOwned, Cow};
-use crate::collections::CollectionAllocErr;
+use crate::collections::TryReserveError;
 use crate::boxed::Box;
 use crate::raw_vec::RawVec;
 
@@ -498,9 +498,9 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     ///
-    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> {
+    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
     ///     let mut output = Vec::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -516,7 +516,7 @@
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> {
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.buf.try_reserve(self.len, additional)
     }
 
@@ -538,9 +538,9 @@
     ///
     /// ```
     /// #![feature(try_reserve)]
-    /// use std::collections::CollectionAllocErr;
+    /// use std::collections::TryReserveError;
     ///
-    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, CollectionAllocErr> {
+    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
     ///     let mut output = Vec::new();
     ///
     ///     // Pre-reserve the memory, exiting if we can't
@@ -556,7 +556,7 @@
     /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
     /// ```
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), CollectionAllocErr>  {
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError>  {
         self.buf.try_reserve_exact(self.len, additional)
     }
 
diff --git a/src/libcore/clone.rs b/src/libcore/clone.rs
index ec22a7c..ec70d39 100644
--- a/src/libcore/clone.rs
+++ b/src/libcore/clone.rs
@@ -135,7 +135,7 @@
 
 /// Derive macro generating an impl of the trait `Clone`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics, derive_clone_copy)]
 pub macro Clone($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
index b802216..cb9feb0 100644
--- a/src/libcore/cmp.rs
+++ b/src/libcore/cmp.rs
@@ -202,7 +202,7 @@
 
 /// Derive macro generating an impl of the trait `PartialEq`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics)]
 pub macro PartialEq($item:item) { /* compiler built-in */ }
@@ -265,7 +265,7 @@
 
 /// Derive macro generating an impl of the trait `Eq`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics, derive_eq)]
 pub macro Eq($item:item) { /* compiler built-in */ }
@@ -616,7 +616,7 @@
 
 /// Derive macro generating an impl of the trait `Ord`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics)]
 pub macro Ord($item:item) { /* compiler built-in */ }
@@ -865,7 +865,7 @@
 
 /// Derive macro generating an impl of the trait `PartialOrd`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics)]
 pub macro PartialOrd($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/default.rs b/src/libcore/default.rs
index 9b1616c..66acc51 100644
--- a/src/libcore/default.rs
+++ b/src/libcore/default.rs
@@ -117,7 +117,7 @@
 
 /// Derive macro generating an impl of the trait `Default`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics)]
 pub macro Default($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/fmt/builders.rs b/src/libcore/fmt/builders.rs
index cb4e326..15ce227 100644
--- a/src/libcore/fmt/builders.rs
+++ b/src/libcore/fmt/builders.rs
@@ -98,7 +98,7 @@
     has_fields: bool,
 }
 
-pub fn debug_struct_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>,
+pub(super) fn debug_struct_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>,
                                 name: &str)
                                 -> DebugStruct<'a, 'b> {
     let result = fmt.write_str(name);
@@ -251,7 +251,10 @@
     empty_name: bool,
 }
 
-pub fn debug_tuple_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>, name: &str) -> DebugTuple<'a, 'b> {
+pub(super) fn debug_tuple_new<'a, 'b>(
+    fmt: &'a mut fmt::Formatter<'b>,
+    name: &str,
+) -> DebugTuple<'a, 'b> {
     let result = fmt.write_str(name);
     DebugTuple {
         fmt,
@@ -418,7 +421,7 @@
     inner: DebugInner<'a, 'b>,
 }
 
-pub fn debug_set_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugSet<'a, 'b> {
+pub(super) fn debug_set_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugSet<'a, 'b> {
     let result = fmt.write_str("{");
     DebugSet {
         inner: DebugInner {
@@ -555,7 +558,7 @@
     inner: DebugInner<'a, 'b>,
 }
 
-pub fn debug_list_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugList<'a, 'b> {
+pub(super) fn debug_list_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugList<'a, 'b> {
     let result = fmt.write_str("[");
     DebugList {
         inner: DebugInner {
@@ -697,7 +700,7 @@
     state: PadAdapterState,
 }
 
-pub fn debug_map_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugMap<'a, 'b> {
+pub(super) fn debug_map_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugMap<'a, 'b> {
     let result = fmt.write_str("{");
     DebugMap {
         fmt,
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index d5fae9e..bd31d25 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -549,7 +549,7 @@
 pub(crate) mod macros {
     /// Derive macro generating an impl of the trait `Debug`.
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
+    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro Debug($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/hash/mod.rs b/src/libcore/hash/mod.rs
index b397119..bf3daa3 100644
--- a/src/libcore/hash/mod.rs
+++ b/src/libcore/hash/mod.rs
@@ -202,7 +202,7 @@
 pub(crate) mod macros {
     /// Derive macro generating an impl of the trait `Hash`.
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
+    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro Hash($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index ceaa870..d145f22 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -1293,18 +1293,40 @@
     /// The stabilized versions of this intrinsic are available on the integer
     /// primitives via the `wrapping_add` method. For example,
     /// [`std::u32::wrapping_add`](../../std/primitive.u32.html#method.wrapping_add)
+    #[cfg(boostrap_stdarch_ignore_this)]
     pub fn overflowing_add<T>(a: T, b: T) -> T;
     /// Returns (a - b) mod 2<sup>N</sup>, where N is the width of T in bits.
     /// The stabilized versions of this intrinsic are available on the integer
     /// primitives via the `wrapping_sub` method. For example,
     /// [`std::u32::wrapping_sub`](../../std/primitive.u32.html#method.wrapping_sub)
+    #[cfg(boostrap_stdarch_ignore_this)]
     pub fn overflowing_sub<T>(a: T, b: T) -> T;
     /// Returns (a * b) mod 2<sup>N</sup>, where N is the width of T in bits.
     /// The stabilized versions of this intrinsic are available on the integer
     /// primitives via the `wrapping_mul` method. For example,
     /// [`std::u32::wrapping_mul`](../../std/primitive.u32.html#method.wrapping_mul)
+    #[cfg(boostrap_stdarch_ignore_this)]
     pub fn overflowing_mul<T>(a: T, b: T) -> T;
 
+    /// Returns (a + b) mod 2<sup>N</sup>, where N is the width of T in bits.
+    /// The stabilized versions of this intrinsic are available on the integer
+    /// primitives via the `wrapping_add` method. For example,
+    /// [`std::u32::wrapping_add`](../../std/primitive.u32.html#method.wrapping_add)
+    #[cfg(not(boostrap_stdarch_ignore_this))]
+    pub fn wrapping_add<T>(a: T, b: T) -> T;
+    /// Returns (a - b) mod 2<sup>N</sup>, where N is the width of T in bits.
+    /// The stabilized versions of this intrinsic are available on the integer
+    /// primitives via the `wrapping_sub` method. For example,
+    /// [`std::u32::wrapping_sub`](../../std/primitive.u32.html#method.wrapping_sub)
+    #[cfg(not(boostrap_stdarch_ignore_this))]
+    pub fn wrapping_sub<T>(a: T, b: T) -> T;
+    /// Returns (a * b) mod 2<sup>N</sup>, where N is the width of T in bits.
+    /// The stabilized versions of this intrinsic are available on the integer
+    /// primitives via the `wrapping_mul` method. For example,
+    /// [`std::u32::wrapping_mul`](../../std/primitive.u32.html#method.wrapping_mul)
+    #[cfg(not(boostrap_stdarch_ignore_this))]
+    pub fn wrapping_mul<T>(a: T, b: T) -> T;
+
     /// Computes `a + b`, while saturating at numeric bounds.
     /// The stabilized versions of this intrinsic are available on the integer
     /// primitives via the `saturating_add` method. For example,
diff --git a/src/libcore/iter/adapters/chain.rs b/src/libcore/iter/adapters/chain.rs
index 76239eb..0b9f7f6 100644
--- a/src/libcore/iter/adapters/chain.rs
+++ b/src/libcore/iter/adapters/chain.rs
@@ -207,6 +207,29 @@
         }
     }
 
+    #[inline]
+    fn nth_back(&mut self, mut n: usize) -> Option<A::Item> {
+        match self.state {
+            ChainState::Both | ChainState::Back => {
+                for x in self.b.by_ref().rev() {
+                    if n == 0 {
+                        return Some(x)
+                    }
+                    n -= 1;
+                }
+                if let ChainState::Both = self.state {
+                    self.state = ChainState::Front;
+                }
+            }
+            ChainState::Front => {}
+        }
+        if let ChainState::Front = self.state {
+            self.a.nth_back(n)
+        } else {
+            None
+        }
+    }
+
     fn try_rfold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R where
         Self: Sized, F: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
     {
diff --git a/src/libcore/iter/adapters/flatten.rs b/src/libcore/iter/adapters/flatten.rs
index e3c8565..a45173f 100644
--- a/src/libcore/iter/adapters/flatten.rs
+++ b/src/libcore/iter/adapters/flatten.rs
@@ -72,8 +72,7 @@
 impl<I: DoubleEndedIterator, U, F> DoubleEndedIterator for FlatMap<I, U, F>
 where
     F: FnMut(I::Item) -> U,
-    U: IntoIterator,
-    U::IntoIter: DoubleEndedIterator,
+    U: IntoIterator<IntoIter: DoubleEndedIterator>,
 {
     #[inline]
     fn next_back(&mut self) -> Option<U::Item> { self.inner.next_back() }
@@ -107,10 +106,7 @@
 /// [`Iterator`]: trait.Iterator.html
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 #[stable(feature = "iterator_flatten", since = "1.29.0")]
-pub struct Flatten<I: Iterator>
-where
-    I::Item: IntoIterator,
-{
+pub struct Flatten<I: Iterator<Item: IntoIterator>> {
     inner: FlattenCompat<I, <I::Item as IntoIterator>::IntoIter>,
 }
 
diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs
index 58e0a70..a63434a 100644
--- a/src/libcore/iter/adapters/mod.rs
+++ b/src/libcore/iter/adapters/mod.rs
@@ -405,6 +405,36 @@
             _ => (usize::MAX, None)
         }
     }
+
+    #[inline]
+    fn try_fold<Acc, F, R>(&mut self, mut acc: Acc, mut f: F) -> R
+    where
+        F: FnMut(Acc, Self::Item) -> R,
+        R: Try<Ok = Acc>,
+    {
+        // fully iterate the current iterator. this is necessary because
+        // `self.iter` may be empty even when `self.orig` isn't
+        acc = self.iter.try_fold(acc, &mut f)?;
+        self.iter = self.orig.clone();
+
+        // complete a full cycle, keeping track of whether the cycled
+        // iterator is empty or not. we need to return early in case
+        // of an empty iterator to prevent an infinite loop
+        let mut is_empty = true;
+        acc = self.iter.try_fold(acc, |acc, x| {
+            is_empty = false;
+            f(acc, x)
+        })?;
+
+        if is_empty {
+            return Try::from_ok(acc);
+        }
+
+        loop {
+            self.iter = self.orig.clone();
+            acc = self.iter.try_fold(acc, &mut f)?;
+        }
+    }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
diff --git a/src/libcore/iter/traits/double_ended.rs b/src/libcore/iter/traits/double_ended.rs
index 8e5bc9b..006b243 100644
--- a/src/libcore/iter/traits/double_ended.rs
+++ b/src/libcore/iter/traits/double_ended.rs
@@ -69,7 +69,7 @@
     /// Returns the `n`th element from the end of the iterator.
     ///
     /// This is essentially the reversed version of [`nth`]. Although like most indexing
-    /// operations, the count starts from zero, so `nth_back(0)` returns the first value fro
+    /// operations, the count starts from zero, so `nth_back(0)` returns the first value from
     /// the end, `nth_back(1)` the second, and so on.
     ///
     /// Note that all elements between the end and the returned element will be
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index bbed951..6c88a76 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -2,21 +2,21 @@
 ///
 /// For details, see `std::macros`.
 #[macro_export]
-#[allow_internal_unstable(core_panic, __rust_unstable_column)]
+#[allow_internal_unstable(core_panic)]
 #[stable(feature = "core", since = "1.6.0")]
 macro_rules! panic {
     () => (
         $crate::panic!("explicit panic")
     );
     ($msg:expr) => ({
-        $crate::panicking::panic(&($msg, file!(), line!(), __rust_unstable_column!()))
+        $crate::panicking::panic(&($msg, $crate::file!(), $crate::line!(), $crate::column!()))
     });
     ($msg:expr,) => (
         $crate::panic!($msg)
     );
     ($fmt:expr, $($arg:tt)+) => ({
-        $crate::panicking::panic_fmt(format_args!($fmt, $($arg)+),
-                                     &(file!(), line!(), __rust_unstable_column!()))
+        $crate::panicking::panic_fmt($crate::format_args!($fmt, $($arg)+),
+                                     &($crate::file!(), $crate::line!(), $crate::column!()))
     });
 }
 
@@ -70,7 +70,7 @@
                     panic!(r#"assertion failed: `(left == right)`
   left: `{:?}`,
  right: `{:?}`: {}"#, &*left_val, &*right_val,
-                           format_args!($($arg)+))
+                           $crate::format_args!($($arg)+))
                 }
             }
         }
@@ -127,7 +127,7 @@
                     panic!(r#"assertion failed: `(left != right)`
   left: `{:?}`,
  right: `{:?}`: {}"#, &*left_val, &*right_val,
-                           format_args!($($arg)+))
+                           $crate::format_args!($($arg)+))
                 }
             }
         }
@@ -181,7 +181,7 @@
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! debug_assert {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { assert!($($arg)*); })
+    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert!($($arg)*); })
 }
 
 /// Asserts that two expressions are equal to each other.
@@ -208,7 +208,7 @@
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! debug_assert_eq {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
+    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
 }
 
 /// Asserts that two expressions are not equal to each other.
@@ -235,7 +235,7 @@
 #[macro_export]
 #[stable(feature = "assert_ne", since = "1.13.0")]
 macro_rules! debug_assert_ne {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
+    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
 }
 
 /// Unwraps a result or propagates its error.
@@ -386,7 +386,7 @@
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! write {
-    ($dst:expr, $($arg:tt)*) => ($dst.write_fmt(format_args!($($arg)*)))
+    ($dst:expr, $($arg:tt)*) => ($dst.write_fmt($crate::format_args!($($arg)*)))
 }
 
 /// Write formatted data into a buffer, with a newline appended.
@@ -446,7 +446,7 @@
         $crate::writeln!($dst)
     );
     ($dst:expr, $($arg:tt)*) => (
-        $dst.write_fmt(format_args_nl!($($arg)*))
+        $dst.write_fmt($crate::format_args_nl!($($arg)*))
     );
 }
 
@@ -515,7 +515,7 @@
         $crate::unreachable!($msg)
     });
     ($fmt:expr, $($arg:tt)*) => ({
-        panic!(concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)
+        panic!($crate::concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)
     });
 }
 
@@ -573,7 +573,7 @@
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! unimplemented {
     () => (panic!("not yet implemented"));
-    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)+)));
+    ($($arg:tt)+) => (panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
 }
 
 /// Indicates unfinished code.
@@ -632,7 +632,7 @@
 #[unstable(feature = "todo_macro", issue = "59277")]
 macro_rules! todo {
     () => (panic!("not yet implemented"));
-    ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)+)));
+    ($($arg:tt)+) => (panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
 }
 
 /// Definitions of built-in macros.
@@ -927,13 +927,6 @@
     #[macro_export]
     macro_rules! column { () => { /* compiler built-in */ } }
 
-    /// Same as `column`, but less likely to be shadowed.
-    #[unstable(feature = "__rust_unstable_column", issue = "0",
-               reason = "internal implementation detail of the `panic` macro")]
-    #[rustc_builtin_macro]
-    #[macro_export]
-    macro_rules! __rust_unstable_column { () => { /* compiler built-in */ } }
-
     /// Expands to the file name in which it was invoked.
     ///
     /// With [`line!`] and [`column!`], these macros provide debugging information for
@@ -1270,14 +1263,14 @@
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
+    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
     pub macro RustcDecodable($item:item) { /* compiler built-in */ }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
     #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
+    #[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro RustcEncodable($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index 3befd42..89af252 100644
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -290,7 +290,7 @@
 
 /// Derive macro generating an impl of the trait `Copy`.
 #[rustc_builtin_macro]
-#[rustc_macro_transparency = "semitransparent"]
+#[cfg_attr(boostrap_stdarch_ignore_this, rustc_macro_transparency = "semitransparent")]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics, derive_clone_copy)]
 pub macro Copy($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 67e30e7..b46e06f 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1112,7 +1112,13 @@
                           without modifying the original"]
             #[inline]
             pub const fn wrapping_add(self, rhs: Self) -> Self {
-                intrinsics::overflowing_add(self, rhs)
+                #[cfg(boostrap_stdarch_ignore_this)] {
+                    intrinsics::overflowing_add(self, rhs)
+                }
+
+                #[cfg(not(boostrap_stdarch_ignore_this))] {
+                    intrinsics::wrapping_add(self, rhs)
+                }
             }
         }
 
@@ -1135,7 +1141,13 @@
                           without modifying the original"]
             #[inline]
             pub const fn wrapping_sub(self, rhs: Self) -> Self {
-                intrinsics::overflowing_sub(self, rhs)
+                #[cfg(boostrap_stdarch_ignore_this)] {
+                    intrinsics::overflowing_sub(self, rhs)
+                }
+
+                #[cfg(not(boostrap_stdarch_ignore_this))] {
+                    intrinsics::wrapping_sub(self, rhs)
+                }
             }
         }
 
@@ -1157,7 +1169,13 @@
                           without modifying the original"]
             #[inline]
             pub const fn wrapping_mul(self, rhs: Self) -> Self {
-                intrinsics::overflowing_mul(self, rhs)
+                #[cfg(boostrap_stdarch_ignore_this)] {
+                    intrinsics::overflowing_mul(self, rhs)
+                }
+
+                #[cfg(not(boostrap_stdarch_ignore_this))] {
+                    intrinsics::wrapping_mul(self, rhs)
+                }
             }
         }
 
@@ -3031,7 +3049,13 @@
                           without modifying the original"]
             #[inline]
             pub const fn wrapping_add(self, rhs: Self) -> Self {
-                intrinsics::overflowing_add(self, rhs)
+                #[cfg(boostrap_stdarch_ignore_this)] {
+                    intrinsics::overflowing_add(self, rhs)
+                }
+
+                #[cfg(not(boostrap_stdarch_ignore_this))] {
+                    intrinsics::wrapping_add(self, rhs)
+                }
             }
         }
 
@@ -3053,7 +3077,13 @@
                           without modifying the original"]
             #[inline]
             pub const fn wrapping_sub(self, rhs: Self) -> Self {
-                intrinsics::overflowing_sub(self, rhs)
+                #[cfg(boostrap_stdarch_ignore_this)] {
+                    intrinsics::overflowing_sub(self, rhs)
+                }
+
+                #[cfg(not(boostrap_stdarch_ignore_this))] {
+                    intrinsics::wrapping_sub(self, rhs)
+                }
             }
         }
 
@@ -3076,7 +3106,13 @@
                           without modifying the original"]
         #[inline]
         pub const fn wrapping_mul(self, rhs: Self) -> Self {
-            intrinsics::overflowing_mul(self, rhs)
+            #[cfg(boostrap_stdarch_ignore_this)] {
+                intrinsics::overflowing_mul(self, rhs)
+            }
+
+            #[cfg(not(boostrap_stdarch_ignore_this))] {
+                intrinsics::wrapping_mul(self, rhs)
+            }
         }
 
         doc_comment! {
diff --git a/src/libcore/prelude/v1.rs b/src/libcore/prelude/v1.rs
index 7624037..7cc279a 100644
--- a/src/libcore/prelude/v1.rs
+++ b/src/libcore/prelude/v1.rs
@@ -56,7 +56,6 @@
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[doc(no_inline)]
 pub use crate::{
-    __rust_unstable_column,
     asm,
     assert,
     cfg,
diff --git a/src/libcore/ptr/unique.rs b/src/libcore/ptr/unique.rs
index f0d011f..3521dd7 100644
--- a/src/libcore/ptr/unique.rs
+++ b/src/libcore/ptr/unique.rs
@@ -122,6 +122,14 @@
     pub unsafe fn as_mut(&mut self) -> &mut T {
         &mut *self.as_ptr()
     }
+
+    /// Casts to a pointer of another type.
+    #[inline]
+    pub const fn cast<U>(self) -> Unique<U> {
+        unsafe {
+            Unique::new_unchecked(self.as_ptr() as *mut U)
+        }
+    }
 }
 
 #[unstable(feature = "ptr_internals", issue = "0")]
diff --git a/src/libcore/tests/iter.rs b/src/libcore/tests/iter.rs
index 3615fab..a1a27e1 100644
--- a/src/libcore/tests/iter.rs
+++ b/src/libcore/tests/iter.rs
@@ -104,6 +104,22 @@
 }
 
 #[test]
+fn test_iterator_chain_nth_back() {
+    let xs = [0, 1, 2, 3, 4, 5];
+    let ys = [30, 40, 50, 60];
+    let zs = [];
+    let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
+    for (i, x) in expected.iter().rev().enumerate() {
+        assert_eq!(Some(x), xs.iter().chain(&ys).nth_back(i));
+    }
+    assert_eq!(zs.iter().chain(&xs).nth_back(0), Some(&5));
+
+    let mut it = xs.iter().chain(&zs);
+    assert_eq!(it.nth_back(5), Some(&0));
+    assert_eq!(it.next(), None);
+}
+
+#[test]
 fn test_iterator_chain_last() {
     let xs = [0, 1, 2, 3, 4, 5];
     let ys = [30, 40, 50, 60];
@@ -1136,6 +1152,18 @@
     assert_eq!(empty::<i32>().cycle().fold(0, |acc, x| acc + x), 0);
 
     assert_eq!(once(1).cycle().skip(1).take(4).fold(0, |acc, x| acc + x), 4);
+
+    assert_eq!((0..10).cycle().take(5).sum::<i32>(), 10);
+    assert_eq!((0..10).cycle().take(15).sum::<i32>(), 55);
+    assert_eq!((0..10).cycle().take(25).sum::<i32>(), 100);
+
+    let mut iter = (0..10).cycle();
+    iter.nth(14);
+    assert_eq!(iter.take(8).sum::<i32>(), 38);
+
+    let mut iter = (0..10).cycle();
+    iter.nth(9);
+    assert_eq!(iter.take(3).sum::<i32>(), 3);
 }
 
 #[test]
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 9e5d637..0f6e834 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -67,7 +67,7 @@
 use syntax::ext::base::SpecialDerives;
 use syntax::ext::hygiene::ExpnId;
 use syntax::print::pprust;
-use syntax::source_map::{respan, ExpnInfo, ExpnKind, DesugaringKind, Spanned};
+use syntax::source_map::{respan, ExpnData, ExpnKind, DesugaringKind, Spanned};
 use syntax::symbol::{kw, sym, Symbol};
 use syntax::tokenstream::{TokenStream, TokenTree};
 use syntax::parse::token::{self, Token};
@@ -704,10 +704,9 @@
         span: Span,
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
     ) -> Span {
-        span.fresh_expansion(ExpnId::root(), ExpnInfo {
-            def_site: span,
+        span.fresh_expansion(ExpnData {
             allow_internal_unstable,
-            ..ExpnInfo::default(ExpnKind::Desugaring(reason), span, self.sess.edition())
+            ..ExpnData::default(ExpnKind::Desugaring(reason), span, self.sess.edition())
         })
     }
 
@@ -1224,7 +1223,7 @@
                     P(hir::Path {
                         res,
                         segments: hir_vec![hir::PathSegment::from_ident(
-                            Ident::with_empty_ctxt(kw::SelfUpper)
+                            Ident::with_dummy_span(kw::SelfUpper)
                         )],
                         span: t.span,
                     }),
@@ -1558,7 +1557,7 @@
 
                     let (name, kind) = match name {
                         hir::LifetimeName::Underscore => (
-                            hir::ParamName::Plain(Ident::with_empty_ctxt(kw::UnderscoreLifetime)),
+                            hir::ParamName::Plain(Ident::with_dummy_span(kw::UnderscoreLifetime)),
                             hir::LifetimeParamKind::Elided,
                         ),
                         hir::LifetimeName::Param(param_name) => (
@@ -2002,7 +2001,7 @@
                         bindings: hir_vec![
                             hir::TypeBinding {
                                 hir_id: this.next_id(),
-                                ident: Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                                ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
                                 kind: hir::TypeBindingKind::Equality {
                                     ty: output
                                         .as_ref()
@@ -2394,7 +2393,7 @@
         let future_params = P(hir::GenericArgs {
             args: hir_vec![],
             bindings: hir_vec![hir::TypeBinding {
-                ident: Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
                 kind: hir::TypeBindingKind::Equality {
                     ty: output_ty,
                 },
diff --git a/src/librustc/hir/lowering/expr.rs b/src/librustc/hir/lowering/expr.rs
index e3a5400..ff0c44a 100644
--- a/src/librustc/hir/lowering/expr.rs
+++ b/src/librustc/hir/lowering/expr.rs
@@ -552,7 +552,7 @@
 
         // let mut pinned = <expr>;
         let expr = P(self.lower_expr(expr));
-        let pinned_ident = Ident::with_empty_ctxt(sym::pinned);
+        let pinned_ident = Ident::with_dummy_span(sym::pinned);
         let (pinned_pat, pinned_pat_hid) = self.pat_ident_binding_mode(
             span,
             pinned_ident,
@@ -593,7 +593,7 @@
         let loop_node_id = self.sess.next_node_id();
         let loop_hir_id = self.lower_node_id(loop_node_id);
         let ready_arm = {
-            let x_ident = Ident::with_empty_ctxt(sym::result);
+            let x_ident = Ident::with_dummy_span(sym::result);
             let (x_pat, x_pat_hid) = self.pat_ident(span, x_ident);
             let x_expr = P(self.expr_ident(span, x_ident, x_pat_hid));
             let ready_pat = self.pat_std_enum(
@@ -984,7 +984,6 @@
             volatile: asm.volatile,
             alignstack: asm.alignstack,
             dialect: asm.dialect,
-            ctxt: asm.ctxt,
         };
 
         let outputs = asm.outputs
@@ -1070,9 +1069,9 @@
         );
         head.span = desugared_span;
 
-        let iter = Ident::with_empty_ctxt(sym::iter);
+        let iter = Ident::with_dummy_span(sym::iter);
 
-        let next_ident = Ident::with_empty_ctxt(sym::__next);
+        let next_ident = Ident::with_dummy_span(sym::__next);
         let (next_pat, next_pat_hid) = self.pat_ident_binding_mode(
             desugared_span,
             next_ident,
@@ -1081,7 +1080,7 @@
 
         // `::std::option::Option::Some(val) => __next = val`
         let pat_arm = {
-            let val_ident = Ident::with_empty_ctxt(sym::val);
+            let val_ident = Ident::with_dummy_span(sym::val);
             let (val_pat, val_pat_hid) = self.pat_ident(pat.span, val_ident);
             let val_expr = P(self.expr_ident(pat.span, val_ident, val_pat_hid));
             let next_expr = P(self.expr_ident(pat.span, next_ident, next_pat_hid));
@@ -1247,7 +1246,7 @@
 
         // `Ok(val) => #[allow(unreachable_code)] val,`
         let ok_arm = {
-            let val_ident = Ident::with_empty_ctxt(sym::val);
+            let val_ident = Ident::with_dummy_span(sym::val);
             let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
             let val_expr = P(self.expr_ident_with_attrs(
                 span,
@@ -1263,7 +1262,7 @@
         // `Err(err) => #[allow(unreachable_code)]
         //              return Try::from_error(From::from(err)),`
         let err_arm = {
-            let err_ident = Ident::with_empty_ctxt(sym::err);
+            let err_ident = Ident::with_dummy_span(sym::err);
             let (err_local, err_local_nid) = self.pat_ident(try_span, err_ident);
             let from_expr = {
                 let from_path = &[sym::convert, sym::From, sym::from];
diff --git a/src/librustc/hir/lowering/item.rs b/src/librustc/hir/lowering/item.rs
index 51a0c41..4f9a9ed 100644
--- a/src/librustc/hir/lowering/item.rs
+++ b/src/librustc/hir/lowering/item.rs
@@ -750,10 +750,7 @@
     }
 
     fn lower_global_asm(&mut self, ga: &GlobalAsm) -> P<hir::GlobalAsm> {
-        P(hir::GlobalAsm {
-            asm: ga.asm,
-            ctxt: ga.ctxt,
-        })
+        P(hir::GlobalAsm { asm: ga.asm })
     }
 
     fn lower_variant(&mut self, v: &Variant) -> hir::Variant {
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 7c2f990..e5ada1f 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -23,7 +23,6 @@
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, AsmDialect};
 use syntax::ast::{Attribute, Label, LitKind, StrStyle, FloatTy, IntTy, UintTy};
 use syntax::attr::{InlineAttr, OptimizeAttr};
-use syntax::ext::hygiene::SyntaxContext;
 use syntax::symbol::{Symbol, kw};
 use syntax::tokenstream::TokenStream;
 use syntax::util::parser::ExprPrecedence;
@@ -202,7 +201,7 @@
         match *self {
             ParamName::Plain(ident) => ident,
             ParamName::Fresh(_) |
-            ParamName::Error => Ident::with_empty_ctxt(kw::UnderscoreLifetime),
+            ParamName::Error => Ident::with_dummy_span(kw::UnderscoreLifetime),
         }
     }
 
@@ -237,8 +236,8 @@
     pub fn ident(&self) -> Ident {
         match *self {
             LifetimeName::Implicit | LifetimeName::Error => Ident::invalid(),
-            LifetimeName::Underscore => Ident::with_empty_ctxt(kw::UnderscoreLifetime),
-            LifetimeName::Static => Ident::with_empty_ctxt(kw::StaticLifetime),
+            LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
+            LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
             LifetimeName::Param(param_name) => param_name.ident(),
         }
     }
@@ -2004,8 +2003,6 @@
     pub volatile: bool,
     pub alignstack: bool,
     pub dialect: AsmDialect,
-    #[stable_hasher(ignore)] // This is used for error reporting
-    pub ctxt: SyntaxContext,
 }
 
 /// Represents an argument in a function header.
@@ -2184,8 +2181,6 @@
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
 pub struct GlobalAsm {
     pub asm: Symbol,
-    #[stable_hasher(ignore)] // This is used for error reporting
-    pub ctxt: SyntaxContext,
 }
 
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable)]
diff --git a/src/librustc/hir/print.rs b/src/librustc/hir/print.rs
index caf8220..2fd683e 100644
--- a/src/librustc/hir/print.rs
+++ b/src/librustc/hir/print.rs
@@ -1457,7 +1457,7 @@
     }
 
     pub fn print_name(&mut self, name: ast::Name) {
-        self.print_ident(ast::Ident::with_empty_ctxt(name))
+        self.print_ident(ast::Ident::with_dummy_span(name))
     }
 
     pub fn print_for_decl(&mut self, loc: &hir::Local, coll: &hir::Expr) {
diff --git a/src/librustc/ich/hcx.rs b/src/librustc/ich/hcx.rs
index ae7d82c..e77faea 100644
--- a/src/librustc/ich/hcx.rs
+++ b/src/librustc/ich/hcx.rs
@@ -350,7 +350,7 @@
         let line_col_len = col | line | len;
         std_hash::Hash::hash(&line_col_len, hasher);
 
-        if span.ctxt == SyntaxContext::empty() {
+        if span.ctxt == SyntaxContext::root() {
             TAG_NO_EXPANSION.hash_stable(hcx, hasher);
         } else {
             TAG_EXPANSION.hash_stable(hcx, hasher);
@@ -370,7 +370,7 @@
                 }
 
                 let mut hasher = StableHasher::new();
-                expn_id.expn_info().hash_stable(hcx, &mut hasher);
+                expn_id.expn_data().hash_stable(hcx, &mut hasher);
                 let sub_hash: Fingerprint = hasher.finish();
                 let sub_hash = sub_hash.to_smaller_hash();
                 cache.borrow_mut().insert(expn_id, sub_hash);
diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 5cc8324..7003f71 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -397,9 +397,10 @@
     Opaque,
 });
 
-impl_stable_hash_for!(struct ::syntax_pos::hygiene::ExpnInfo {
-    call_site,
+impl_stable_hash_for!(struct ::syntax_pos::hygiene::ExpnData {
     kind,
+    parent -> _,
+    call_site,
     def_site,
     default_transparency,
     allow_internal_unstable,
diff --git a/src/librustc/lint/internal.rs b/src/librustc/lint/internal.rs
index dea1cc6..be73b30 100644
--- a/src/librustc/lint/internal.rs
+++ b/src/librustc/lint/internal.rs
@@ -9,7 +9,6 @@
 use rustc_data_structures::fx::FxHashMap;
 use syntax::ast::{Ident, Item, ItemKind};
 use syntax::symbol::{sym, Symbol};
-use syntax_pos::ExpnInfo;
 
 declare_tool_lint! {
     pub rustc::DEFAULT_HASH_TYPES,
@@ -108,7 +107,7 @@
                             .help("try using `Ty` instead")
                             .emit();
                         } else {
-                            if ty.span.ctxt().outer_expn_info().is_some() {
+                            if ty.span.from_expansion() {
                                 return;
                             }
                             if let Some(t) = is_ty_or_ty_ctxt(cx, ty) {
@@ -228,30 +227,20 @@
         if let ItemKind::Impl(_, _, _, _, Some(lint_pass), _, _) = &item.node {
             if let Some(last) = lint_pass.path.segments.last() {
                 if last.ident.name == sym::LintPass {
-                    match &lint_pass.path.span.ctxt().outer_expn_info() {
-                        Some(info) if is_lint_pass_expansion(info) => {}
-                        _ => {
-                            cx.struct_span_lint(
-                                LINT_PASS_IMPL_WITHOUT_MACRO,
-                                lint_pass.path.span,
-                                "implementing `LintPass` by hand",
-                            )
-                            .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead")
-                            .emit();
-                        }
+                    let expn_data = lint_pass.path.span.ctxt().outer_expn_data();
+                    let call_site = expn_data.call_site;
+                    if expn_data.kind.descr() != sym::impl_lint_pass &&
+                       call_site.ctxt().outer_expn_data().kind.descr() != sym::declare_lint_pass {
+                        cx.struct_span_lint(
+                            LINT_PASS_IMPL_WITHOUT_MACRO,
+                            lint_pass.path.span,
+                            "implementing `LintPass` by hand",
+                        )
+                        .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead")
+                        .emit();
                     }
                 }
             }
         }
     }
 }
-
-fn is_lint_pass_expansion(expn_info: &ExpnInfo) -> bool {
-    if expn_info.kind.descr() == sym::impl_lint_pass {
-        true
-    } else if let Some(info) = expn_info.call_site.ctxt().outer_expn_info() {
-        info.kind.descr() == sym::declare_lint_pass
-    } else {
-        false
-    }
-}
diff --git a/src/librustc/lint/mod.rs b/src/librustc/lint/mod.rs
index 8cb5b1e..2b58627 100644
--- a/src/librustc/lint/mod.rs
+++ b/src/librustc/lint/mod.rs
@@ -885,21 +885,16 @@
 /// This is used to test whether a lint should not even begin to figure out whether it should
 /// be reported on the current node.
 pub fn in_external_macro(sess: &Session, span: Span) -> bool {
-    let info = match span.ctxt().outer_expn_info() {
-        Some(info) => info,
-        // no ExpnInfo means this span doesn't come from a macro
-        None => return false,
-    };
-
-    match info.kind {
+    let expn_data = span.ctxt().outer_expn_data();
+    match expn_data.kind {
         ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) => false,
         ExpnKind::Desugaring(_) => true, // well, it's "external"
         ExpnKind::Macro(MacroKind::Bang, _) => {
-            if info.def_site.is_dummy() {
+            if expn_data.def_site.is_dummy() {
                 // dummy span for the def_site means it's an external macro
                 return true;
             }
-            match sess.source_map().span_to_snippet(info.def_site) {
+            match sess.source_map().span_to_snippet(expn_data.def_site) {
                 Ok(code) => !code.starts_with("macro_rules"),
                 // no snippet = external macro or compiler-builtin expansion
                 Err(_) => true,
@@ -911,10 +906,8 @@
 
 /// Returns whether `span` originates in a derive macro's expansion
 pub fn in_derive_expansion(span: Span) -> bool {
-    if let Some(info) = span.ctxt().outer_expn_info() {
-        if let ExpnKind::Macro(MacroKind::Derive, _) = info.kind {
-            return true;
-        }
+    if let ExpnKind::Macro(MacroKind::Derive, _) = span.ctxt().outer_expn_data().kind {
+        return true;
     }
     false
 }
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index d37b236..de84fcd 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -178,8 +178,7 @@
                           -> Result<MetadataRef, String>;
 }
 
-/// A store of Rust crates, through with their metadata
-/// can be accessed.
+/// A store of Rust crates, through which their metadata can be accessed.
 ///
 /// Note that this trait should probably not be expanding today. All new
 /// functionality should be driven through queries instead!
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 1e2ec08..11701a6 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -2197,7 +2197,6 @@
         let ty = tcx.type_of(def_id).subst(tcx, substs);
         Operand::Constant(box Constant {
             span,
-            ty,
             user_ty: None,
             literal: ty::Const::zero_sized(tcx, ty),
         })
@@ -2476,7 +2475,6 @@
 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
 pub struct Constant<'tcx> {
     pub span: Span,
-    pub ty: Ty<'tcx>,
 
     /// Optional user-given type: for something like
     /// `collect::<Vec<_>>`, this would be present and would
@@ -3385,12 +3383,11 @@
     fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
         Constant {
             span: self.span.clone(),
-            ty: self.ty.fold_with(folder),
             user_ty: self.user_ty.fold_with(folder),
             literal: self.literal.fold_with(folder),
         }
     }
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        self.ty.visit_with(visitor) || self.literal.visit_with(visitor)
+        self.literal.visit_with(visitor)
     }
 }
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
index f888938..e9f7636 100644
--- a/src/librustc/mir/tcx.rs
+++ b/src/librustc/mir/tcx.rs
@@ -252,7 +252,7 @@
         match self {
             &Operand::Copy(ref l) |
             &Operand::Move(ref l) => l.ty(local_decls, tcx).ty,
-            &Operand::Constant(ref c) => c.ty,
+            &Operand::Constant(ref c) => c.literal.ty,
         }
     }
 }
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index ee4ecb6..2d16e7b 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -782,13 +782,11 @@
                               location: Location) {
                 let Constant {
                     span,
-                    ty,
                     user_ty,
                     literal,
                 } = constant;
 
                 self.visit_span(span);
-                self.visit_ty(ty, TyContext::Location(location));
                 drop(user_ty); // no visit method for this
                 self.visit_const(literal, location);
             }
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 3536b2a..8e3b910 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -395,7 +395,7 @@
         output_types: OutputTypes [TRACKED],
         search_paths: Vec<SearchPath> [UNTRACKED],
         libs: Vec<(String, Option<String>, Option<cstore::NativeLibraryKind>)> [TRACKED],
-        maybe_sysroot: Option<PathBuf> [TRACKED],
+        maybe_sysroot: Option<PathBuf> [UNTRACKED],
 
         target_triple: TargetTriple [TRACKED],
 
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 83bd5c5..ba92e85 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -36,7 +36,7 @@
 use std::fmt;
 use syntax::ast;
 use syntax::symbol::sym;
-use syntax_pos::{DUMMY_SP, Span, ExpnInfo, ExpnKind};
+use syntax_pos::{DUMMY_SP, Span, ExpnKind};
 
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_fulfillment_errors(&self,
@@ -61,9 +61,9 @@
             // We want to ignore desugarings here: spans are equivalent even
             // if one is the result of a desugaring and the other is not.
             let mut span = error.obligation.cause.span;
-            if let Some(ExpnInfo { kind: ExpnKind::Desugaring(_), def_site, .. })
-                    = span.ctxt().outer_expn_info() {
-                span = def_site;
+            let expn_data = span.ctxt().outer_expn_data();
+            if let ExpnKind::Desugaring(_) = expn_data.kind {
+                span = expn_data.call_site;
             }
 
             error_map.entry(span).or_default().push(
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs
index 38263f2..72df45d 100644
--- a/src/librustc/traits/project.rs
+++ b/src/librustc/traits/project.rs
@@ -1417,7 +1417,7 @@
                 projection_ty: ty::ProjectionTy::from_ref_and_name(
                     tcx,
                     trait_ref,
-                    Ident::with_empty_ctxt(FN_OUTPUT_NAME),
+                    Ident::with_dummy_span(FN_OUTPUT_NAME),
                 ),
                 ty: ret_type
             }
diff --git a/src/librustc/ty/query/on_disk_cache.rs b/src/librustc/ty/query/on_disk_cache.rs
index 00871a1cb..8bf0197 100644
--- a/src/librustc/ty/query/on_disk_cache.rs
+++ b/src/librustc/ty/query/on_disk_cache.rs
@@ -23,16 +23,16 @@
 use syntax::ast::NodeId;
 use syntax::source_map::{SourceMap, StableSourceFileId};
 use syntax_pos::{BytePos, Span, DUMMY_SP, SourceFile};
-use syntax_pos::hygiene::{ExpnId, SyntaxContext, ExpnInfo};
+use syntax_pos::hygiene::{ExpnId, SyntaxContext, ExpnData};
 
 const TAG_FILE_FOOTER: u128 = 0xC0FFEE_C0FFEE_C0FFEE_C0FFEE_C0FFEE;
 
 const TAG_CLEAR_CROSS_CRATE_CLEAR: u8 = 0;
 const TAG_CLEAR_CROSS_CRATE_SET: u8 = 1;
 
-const TAG_NO_EXPANSION_INFO: u8 = 0;
-const TAG_EXPANSION_INFO_SHORTHAND: u8 = 1;
-const TAG_EXPANSION_INFO_INLINE: u8 = 2;
+const TAG_NO_EXPN_DATA: u8 = 0;
+const TAG_EXPN_DATA_SHORTHAND: u8 = 1;
+const TAG_EXPN_DATA_INLINE: u8 = 2;
 
 const TAG_VALID_SPAN: u8 = 0;
 const TAG_INVALID_SPAN: u8 = 1;
@@ -58,7 +58,7 @@
 
     // These two fields caches that are populated lazily during decoding.
     file_index_to_file: Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
-    synthetic_expansion_infos: Lock<FxHashMap<AbsoluteBytePos, SyntaxContext>>,
+    synthetic_syntax_contexts: Lock<FxHashMap<AbsoluteBytePos, SyntaxContext>>,
 
     // A map from dep-node to the position of the cached query result in
     // `serialized_data`.
@@ -135,7 +135,7 @@
             current_diagnostics: Default::default(),
             query_result_index: footer.query_result_index.into_iter().collect(),
             prev_diagnostics_index: footer.diagnostics_index.into_iter().collect(),
-            synthetic_expansion_infos: Default::default(),
+            synthetic_syntax_contexts: Default::default(),
             alloc_decoding_state: AllocDecodingState::new(footer.interpret_alloc_index),
         }
     }
@@ -151,7 +151,7 @@
             current_diagnostics: Default::default(),
             query_result_index: Default::default(),
             prev_diagnostics_index: Default::default(),
-            synthetic_expansion_infos: Default::default(),
+            synthetic_syntax_contexts: Default::default(),
             alloc_decoding_state: AllocDecodingState::new(Vec::new()),
         }
     }
@@ -185,7 +185,7 @@
                 encoder,
                 type_shorthands: Default::default(),
                 predicate_shorthands: Default::default(),
-                expn_info_shorthands: Default::default(),
+                expn_data_shorthands: Default::default(),
                 interpret_allocs: Default::default(),
                 interpret_allocs_inverse: Vec::new(),
                 source_map: CachingSourceMapView::new(tcx.sess.source_map()),
@@ -383,7 +383,7 @@
             cnum_map: self.cnum_map.get(),
             file_index_to_file: &self.file_index_to_file,
             file_index_to_stable_id: &self.file_index_to_stable_id,
-            synthetic_expansion_infos: &self.synthetic_expansion_infos,
+            synthetic_syntax_contexts: &self.synthetic_syntax_contexts,
             alloc_decoding_session: self.alloc_decoding_state.new_decoding_session(),
         };
 
@@ -440,7 +440,7 @@
     opaque: opaque::Decoder<'a>,
     source_map: &'a SourceMap,
     cnum_map: &'a IndexVec<CrateNum, Option<CrateNum>>,
-    synthetic_expansion_infos: &'a Lock<FxHashMap<AbsoluteBytePos, SyntaxContext>>,
+    synthetic_syntax_contexts: &'a Lock<FxHashMap<AbsoluteBytePos, SyntaxContext>>,
     file_index_to_file: &'a Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
     file_index_to_stable_id: &'a FxHashMap<SourceFileIndex, StableSourceFileId>,
     alloc_decoding_session: AllocDecodingSession<'a>,
@@ -586,37 +586,37 @@
         let lo = file_lo.lines[line_lo - 1] + col_lo;
         let hi = lo + len;
 
-        let expn_info_tag = u8::decode(self)?;
+        let expn_data_tag = u8::decode(self)?;
 
-        // FIXME(mw): This method does not restore `InternalExpnData::parent` or
+        // FIXME(mw): This method does not restore `ExpnData::parent` or
         // `SyntaxContextData::prev_ctxt` or `SyntaxContextData::opaque`. These things
         // don't seem to be used after HIR lowering, so everything should be fine
         // as long as incremental compilation does not kick in before that.
-        let location = || Span::new(lo, hi, SyntaxContext::empty());
-        let recover_from_expn_info = |this: &Self, expn_info, pos| {
-            let span = location().fresh_expansion(ExpnId::root(), expn_info);
-            this.synthetic_expansion_infos.borrow_mut().insert(pos, span.ctxt());
+        let location = || Span::with_root_ctxt(lo, hi);
+        let recover_from_expn_data = |this: &Self, expn_data, pos| {
+            let span = location().fresh_expansion(expn_data);
+            this.synthetic_syntax_contexts.borrow_mut().insert(pos, span.ctxt());
             span
         };
-        Ok(match expn_info_tag {
-            TAG_NO_EXPANSION_INFO => {
+        Ok(match expn_data_tag {
+            TAG_NO_EXPN_DATA => {
                 location()
             }
-            TAG_EXPANSION_INFO_INLINE => {
-                let expn_info = Decodable::decode(self)?;
-                recover_from_expn_info(
-                    self, expn_info, AbsoluteBytePos::new(self.opaque.position())
+            TAG_EXPN_DATA_INLINE => {
+                let expn_data = Decodable::decode(self)?;
+                recover_from_expn_data(
+                    self, expn_data, AbsoluteBytePos::new(self.opaque.position())
                 )
             }
-            TAG_EXPANSION_INFO_SHORTHAND => {
+            TAG_EXPN_DATA_SHORTHAND => {
                 let pos = AbsoluteBytePos::decode(self)?;
-                let cached_ctxt = self.synthetic_expansion_infos.borrow().get(&pos).cloned();
+                let cached_ctxt = self.synthetic_syntax_contexts.borrow().get(&pos).cloned();
                 if let Some(ctxt) = cached_ctxt {
                     Span::new(lo, hi, ctxt)
                 } else {
-                    let expn_info =
-                        self.with_position(pos.to_usize(), |this| ExpnInfo::decode(this))?;
-                    recover_from_expn_info(self, expn_info, pos)
+                    let expn_data =
+                        self.with_position(pos.to_usize(), |this| ExpnData::decode(this))?;
+                    recover_from_expn_data(self, expn_data, pos)
                 }
             }
             _ => {
@@ -725,7 +725,7 @@
     encoder: &'a mut E,
     type_shorthands: FxHashMap<Ty<'tcx>, usize>,
     predicate_shorthands: FxHashMap<ty::Predicate<'tcx>, usize>,
-    expn_info_shorthands: FxHashMap<ExpnId, AbsoluteBytePos>,
+    expn_data_shorthands: FxHashMap<ExpnId, AbsoluteBytePos>,
     interpret_allocs: FxHashMap<interpret::AllocId, usize>,
     interpret_allocs_inverse: Vec<interpret::AllocId>,
     source_map: CachingSourceMapView<'tcx>,
@@ -816,22 +816,18 @@
         col_lo.encode(self)?;
         len.encode(self)?;
 
-        if span_data.ctxt == SyntaxContext::empty() {
-            TAG_NO_EXPANSION_INFO.encode(self)
+        if span_data.ctxt == SyntaxContext::root() {
+            TAG_NO_EXPN_DATA.encode(self)
         } else {
-            let (expn_id, expn_info) = span_data.ctxt.outer_expn_with_info();
-            if let Some(expn_info) = expn_info {
-                if let Some(pos) = self.expn_info_shorthands.get(&expn_id).cloned() {
-                    TAG_EXPANSION_INFO_SHORTHAND.encode(self)?;
-                    pos.encode(self)
-                } else {
-                    TAG_EXPANSION_INFO_INLINE.encode(self)?;
-                    let pos = AbsoluteBytePos::new(self.position());
-                    self.expn_info_shorthands.insert(expn_id, pos);
-                    expn_info.encode(self)
-                }
+            let (expn_id, expn_data) = span_data.ctxt.outer_expn_with_data();
+            if let Some(pos) = self.expn_data_shorthands.get(&expn_id).cloned() {
+                TAG_EXPN_DATA_SHORTHAND.encode(self)?;
+                pos.encode(self)
             } else {
-                TAG_NO_EXPANSION_INFO.encode(self)
+                TAG_EXPN_DATA_INLINE.encode(self)?;
+                let pos = AbsoluteBytePos::new(self.position());
+                self.expn_data_shorthands.insert(expn_id, pos);
+                expn_data.encode(self)
             }
         }
     }
diff --git a/src/librustc_codegen_llvm/asm.rs b/src/librustc_codegen_llvm/asm.rs
index 9763d52..b68ee2c 100644
--- a/src/librustc_codegen_llvm/asm.rs
+++ b/src/librustc_codegen_llvm/asm.rs
@@ -6,9 +6,9 @@
 
 use rustc::hir;
 use rustc_codegen_ssa::traits::*;
-
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::mir::operand::OperandValue;
+use syntax_pos::Span;
 
 use std::ffi::{CStr, CString};
 use libc::{c_uint, c_char};
@@ -19,7 +19,8 @@
         &mut self,
         ia: &hir::InlineAsm,
         outputs: Vec<PlaceRef<'tcx, &'ll Value>>,
-        mut inputs: Vec<&'ll Value>
+        mut inputs: Vec<&'ll Value>,
+        span: Span,
     ) -> bool {
         let mut ext_constraints = vec![];
         let mut output_types = vec![];
@@ -102,7 +103,7 @@
             let kind = llvm::LLVMGetMDKindIDInContext(self.llcx,
                 key.as_ptr() as *const c_char, key.len() as c_uint);
 
-            let val: &'ll Value = self.const_i32(ia.ctxt.outer_expn().as_u32() as i32);
+            let val: &'ll Value = self.const_i32(span.ctxt().outer_expn().as_u32() as i32);
 
             llvm::LLVMSetMetadata(r, kind,
                 llvm::LLVMMDNodeInContext(self.llcx, &val, 1));
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index a9b8962..9483ffc 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -328,7 +328,7 @@
             },
             "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" |
             "bitreverse" | "add_with_overflow" | "sub_with_overflow" |
-            "mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
+            "mul_with_overflow" | "wrapping_add" | "wrapping_sub" | "wrapping_mul" |
             "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" |
             "unchecked_add" | "unchecked_sub" | "unchecked_mul" | "exact_div" |
             "rotate_left" | "rotate_right" | "saturating_add" | "saturating_sub" => {
@@ -398,9 +398,9 @@
 
                                 return;
                             },
-                            "overflowing_add" => self.add(args[0].immediate(), args[1].immediate()),
-                            "overflowing_sub" => self.sub(args[0].immediate(), args[1].immediate()),
-                            "overflowing_mul" => self.mul(args[0].immediate(), args[1].immediate()),
+                            "wrapping_add" => self.add(args[0].immediate(), args[1].immediate()),
+                            "wrapping_sub" => self.sub(args[0].immediate(), args[1].immediate()),
+                            "wrapping_mul" => self.mul(args[0].immediate(), args[1].immediate()),
                             "exact_div" =>
                                 if signed {
                                     self.exactsdiv(args[0].immediate(), args[1].immediate())
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index c9e4663..eec0984 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -1775,10 +1775,7 @@
                     }
                 }
                 Ok(SharedEmitterMessage::InlineAsmError(cookie, msg)) => {
-                    match ExpnId::from_u32(cookie).expn_info() {
-                        Some(ei) => sess.span_err(ei.call_site, &msg),
-                        None     => sess.err(&msg),
-                    }
+                    sess.span_err(ExpnId::from_u32(cookie).expn_data().call_site, &msg)
                 }
                 Ok(SharedEmitterMessage::AbortIfErrors) => {
                     sess.abort_if_errors();
diff --git a/src/librustc_codegen_ssa/mir/analyze.rs b/src/librustc_codegen_ssa/mir/analyze.rs
index cc0c733..e63f1b9 100644
--- a/src/librustc_codegen_ssa/mir/analyze.rs
+++ b/src/librustc_codegen_ssa/mir/analyze.rs
@@ -221,7 +221,7 @@
             mir::TerminatorKind::Call {
                 func: mir::Operand::Constant(ref c),
                 ref args, ..
-            } => match c.ty.sty {
+            } => match c.literal.ty.sty {
                 ty::FnDef(did, _) => Some((did, args)),
                 _ => None,
             },
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index ce98979..dbce5ce 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -651,7 +651,7 @@
                             let (llval, ty) = self.simd_shuffle_indices(
                                 &bx,
                                 constant.span,
-                                constant.ty,
+                                constant.literal.ty,
                                 c,
                             );
                             return OperandRef {
diff --git a/src/librustc_codegen_ssa/mir/mod.rs b/src/librustc_codegen_ssa/mir/mod.rs
index e7517d6..32bcdeb 100644
--- a/src/librustc_codegen_ssa/mir/mod.rs
+++ b/src/librustc_codegen_ssa/mir/mod.rs
@@ -8,7 +8,7 @@
 use crate::debuginfo::{self, VariableAccess, VariableKind, FunctionDebugContext};
 use crate::traits::*;
 
-use syntax_pos::{DUMMY_SP, NO_EXPANSION, BytePos, Span};
+use syntax_pos::{DUMMY_SP, BytePos, Span};
 use syntax::symbol::kw;
 
 use std::iter;
@@ -120,7 +120,7 @@
         // In order to have a good line stepping behavior in debugger, we overwrite debug
         // locations of macro expansions with that of the outermost expansion site
         // (unless the crate is being compiled with `-Z debug-macros`).
-        if source_info.span.ctxt() == NO_EXPANSION ||
+        if !source_info.span.from_expansion() ||
            self.cx.sess().opts.debugging_opts.debug_macros {
             let scope = self.scope_metadata_for_loc(source_info.scope, source_info.span.lo());
             (scope, source_info.span)
diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs
index 5e5804b..254b73d 100644
--- a/src/librustc_codegen_ssa/mir/operand.rs
+++ b/src/librustc_codegen_ssa/mir/operand.rs
@@ -466,7 +466,6 @@
             }
 
             mir::Operand::Constant(ref constant) => {
-                let ty = self.monomorphize(&constant.ty);
                 self.eval_mir_constant(constant)
                     .map(|c| OperandRef::from_const(bx, c))
                     .unwrap_or_else(|err| {
@@ -481,6 +480,7 @@
                         // the above error (or silence it under some conditions) will not cause UB
                         bx.abort();
                         // We've errored, so we don't have to produce working code.
+                        let ty = self.monomorphize(&constant.literal.ty);
                         let layout = bx.cx().layout_of(ty);
                         bx.load_operand(PlaceRef::new_sized(
                             bx.cx().const_undef(bx.cx().type_ptr_to(bx.cx().backend_type(layout))),
diff --git a/src/librustc_codegen_ssa/mir/statement.rs b/src/librustc_codegen_ssa/mir/statement.rs
index 3717be4..3617f3a 100644
--- a/src/librustc_codegen_ssa/mir/statement.rs
+++ b/src/librustc_codegen_ssa/mir/statement.rs
@@ -89,7 +89,12 @@
                 });
 
                 if input_vals.len() == asm.inputs.len() {
-                    let res = bx.codegen_inline_asm(&asm.asm, outputs, input_vals);
+                    let res = bx.codegen_inline_asm(
+                        &asm.asm,
+                        outputs,
+                        input_vals,
+                        statement.source_info.span,
+                    );
                     if !res {
                         span_err!(bx.sess(), statement.source_info.span, E0668,
                                   "malformed inline assembly");
diff --git a/src/librustc_codegen_ssa/traits/asm.rs b/src/librustc_codegen_ssa/traits/asm.rs
index fd3c868..c9e1ed8 100644
--- a/src/librustc_codegen_ssa/traits/asm.rs
+++ b/src/librustc_codegen_ssa/traits/asm.rs
@@ -1,6 +1,7 @@
 use super::BackendTypes;
 use crate::mir::place::PlaceRef;
 use rustc::hir::{GlobalAsm, InlineAsm};
+use syntax_pos::Span;
 
 pub trait AsmBuilderMethods<'tcx>: BackendTypes {
     /// Take an inline assembly expression and splat it out via LLVM
@@ -9,6 +10,7 @@
         ia: &InlineAsm,
         outputs: Vec<PlaceRef<'tcx, Self::Value>>,
         inputs: Vec<Self::Value>,
+        span: Span,
     ) -> bool;
 }
 
diff --git a/src/librustc_codegen_utils/Cargo.toml b/src/librustc_codegen_utils/Cargo.toml
index d93589e..89b50c5 100644
--- a/src/librustc_codegen_utils/Cargo.toml
+++ b/src/librustc_codegen_utils/Cargo.toml
@@ -13,7 +13,7 @@
 flate2 = "1.0"
 log = "0.4"
 punycode = "0.4.0"
-rustc-demangle = "0.1.15"
+rustc-demangle = "0.1.16"
 
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_codegen_utils/symbol_names/v0.rs b/src/librustc_codegen_utils/symbol_names/v0.rs
index 47601da..8d6a1d7 100644
--- a/src/librustc_codegen_utils/symbol_names/v0.rs
+++ b/src/librustc_codegen_utils/symbol_names/v0.rs
@@ -198,10 +198,14 @@
 
         let lifetimes = regions.into_iter().map(|br| {
             match br {
-                ty::BrAnon(i) => i + 1,
+                ty::BrAnon(i) => {
+                    // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`.
+                    assert_ne!(i, 0);
+                    i - 1
+                },
                 _ => bug!("symbol_names: non-anonymized region `{:?}` in `{:?}`", br, value),
             }
-        }).max().unwrap_or(0);
+        }).max().map_or(0, |max| max + 1);
 
         self.push_opt_integer_62("G", lifetimes as u64);
         lifetime_depths.end += lifetimes;
@@ -297,6 +301,10 @@
             // Late-bound lifetimes use indices starting at 1,
             // see `BinderLevel` for more details.
             ty::ReLateBound(debruijn, ty::BrAnon(i)) => {
+                // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`.
+                assert_ne!(i, 0);
+                let i = i - 1;
+
                 let binder = &self.binders[self.binders.len() - 1 - debruijn.index()];
                 let depth = binder.lifetime_depths.start + i;
 
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index e9d85a5..fdd0773 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -678,7 +678,7 @@
 
                     let mut cfgs = sess.parse_sess.config.iter().filter_map(|&(name, ref value)| {
                         let gated_cfg = GatedCfg::gate(&ast::MetaItem {
-                            path: ast::Path::from_ident(ast::Ident::with_empty_ctxt(name)),
+                            path: ast::Path::from_ident(ast::Ident::with_dummy_span(name)),
                             node: ast::MetaItemKind::Word,
                             span: DUMMY_SP,
                         });
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index f3e5241..4018a66 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -43,8 +43,7 @@
                  SourceFile,
                  FileName,
                  MultiSpan,
-                 Span,
-                 NO_EXPANSION};
+                 Span};
 
 /// Indicates the confidence in the correctness of a suggestion.
 ///
@@ -189,7 +188,7 @@
             // Find the bounding span.
             let lo = substitution.parts.iter().map(|part| part.span.lo()).min().unwrap();
             let hi = substitution.parts.iter().map(|part| part.span.hi()).min().unwrap();
-            let bounding_span = Span::new(lo, hi, NO_EXPANSION);
+            let bounding_span = Span::with_root_ctxt(lo, hi);
             let lines = cm.span_to_lines(bounding_span).unwrap();
             assert!(!lines.lines.is_empty());
 
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 47b4e7c..8216008 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -42,7 +42,7 @@
 use syntax::edition::Edition;
 use syntax::feature_gate::{self, AttributeGate, AttributeType};
 use syntax::feature_gate::{Stability, deprecated_attributes};
-use syntax_pos::{BytePos, Span, SyntaxContext};
+use syntax_pos::{BytePos, Span};
 use syntax::symbol::{Symbol, kw, sym};
 use syntax::errors::{Applicability, DiagnosticBuilder};
 use syntax::print::pprust::expr_to_string;
@@ -78,7 +78,7 @@
         if let ast::ExprKind::While(cond, ..) = &e.node {
             if let ast::ExprKind::Lit(ref lit) = pierce_parens(cond).node {
                 if let ast::LitKind::Bool(true) = lit.node {
-                    if lit.span.ctxt() == SyntaxContext::empty() {
+                    if !lit.span.from_expansion() {
                         let msg = "denote infinite loops with `loop { ... }`";
                         let condition_span = cx.sess.source_map().def_span(e.span);
                         cx.struct_span_lint(WHILE_TRUE, condition_span, msg)
@@ -167,7 +167,7 @@
                 if fieldpat.is_shorthand {
                     continue;
                 }
-                if fieldpat.span.ctxt().outer_expn_info().is_some() {
+                if fieldpat.span.from_expansion() {
                     // Don't lint if this is a macro expansion: macro authors
                     // shouldn't have to worry about this kind of style issue
                     // (Issue #49588)
@@ -1012,7 +1012,7 @@
         let mut applicability = Applicability::MachineApplicable;
         match vis.node {
             hir::VisibilityKind::Public if !cx.access_levels.is_reachable(id) => {
-                if span.ctxt().outer_expn_info().is_some() {
+                if span.from_expansion() {
                     applicability = Applicability::MaybeIncorrect;
                 }
                 let def_span = cx.tcx.sess.source_map().def_span(span);
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index 6a3dfdb..90e4677 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -517,9 +517,8 @@
                 // trigger in situations that macro authors shouldn't have to care about, e.g.,
                 // when a parenthesized token tree matched in one macro expansion is matched as
                 // an expression in another and used as a fn/method argument (Issue #47775)
-                if e.span.ctxt().outer_expn_info()
-                    .map_or(false, |info| info.call_site.ctxt().outer_expn_info().is_some()) {
-                        return;
+                if e.span.ctxt().outer_expn_data().call_site.from_expansion() {
+                    return;
                 }
                 let msg = format!("{} argument", call_kind);
                 for arg in args_to_check {
diff --git a/src/librustc_llvm/build.rs b/src/librustc_llvm/build.rs
index 16cdbb7..40ddd65 100644
--- a/src/librustc_llvm/build.rs
+++ b/src/librustc_llvm/build.rs
@@ -151,6 +151,10 @@
         cfg.define("LLVM_RUSTLLVM", None);
     }
 
+    if env::var_os("LLVM_NDEBUG").is_some() {
+        cfg.define("NDEBUG", None);
+    }
+
     build_helper::rerun_if_changed_anything_in_dir(Path::new("../rustllvm"));
     cfg.file("../rustllvm/PassWrapper.cpp")
        .file("../rustllvm/RustWrapper.cpp")
@@ -250,8 +254,11 @@
     let llvm_use_libcxx = env::var_os("LLVM_USE_LIBCXX");
 
     let stdcppname = if target.contains("openbsd") {
-        // llvm-config on OpenBSD doesn't mention stdlib=libc++
-        "c++"
+        if target.contains("sparc64") {
+            "estdc++"
+        } else {
+            "c++"
+        }
     } else if target.contains("freebsd") {
         "c++"
     } else if target.contains("darwin") {
diff --git a/src/librustc_metadata/cstore.rs b/src/librustc_metadata/cstore.rs
index 5d8fabc..4ac0a5b9 100644
--- a/src/librustc_metadata/cstore.rs
+++ b/src/librustc_metadata/cstore.rs
@@ -70,7 +70,7 @@
     // whichever `TyCtxt` is being used to decode those values.
     pub root: schema::CrateRoot<'static>,
 
-    /// For each public item in this crate, we encode a key. When the
+    /// For each definition in this crate, we encode a key. When the
     /// crate is loaded, we read all the keys and put them in this
     /// hashmap, which gives the reverse mapping. This allows us to
     /// quickly retrace a `DefPath`, which is needed for incremental
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index ee1175e..b46758a 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -35,7 +35,7 @@
 use syntax::parse::source_file_to_stream;
 use syntax::parse::parser::emit_unclosed_delims;
 use syntax::symbol::{Symbol, sym};
-use syntax_pos::{Span, NO_EXPANSION, FileName};
+use syntax_pos::{Span, FileName};
 use rustc_data_structures::bit_set::BitSet;
 
 macro_rules! provide {
@@ -443,7 +443,7 @@
         let source_name = FileName::Macros(macro_full_name);
 
         let source_file = sess.parse_sess.source_map().new_source_file(source_name, def.body);
-        let local_span = Span::new(source_file.start_pos, source_file.end_pos, NO_EXPANSION);
+        let local_span = Span::with_root_ctxt(source_file.start_pos, source_file.end_pos);
         let (body, mut errors) = source_file_to_stream(&sess.parse_sess, source_file, None);
         emit_unclosed_delims(&mut errors, &sess.diagnostic());
 
diff --git a/src/librustc_metadata/decoder.rs b/src/librustc_metadata/decoder.rs
index 935187d..772b2d3 100644
--- a/src/librustc_metadata/decoder.rs
+++ b/src/librustc_metadata/decoder.rs
@@ -32,7 +32,7 @@
 use syntax::symbol::{Symbol, sym};
 use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::hygiene::ExpnId;
-use syntax_pos::{self, Span, BytePos, Pos, DUMMY_SP, NO_EXPANSION};
+use syntax_pos::{self, Span, BytePos, Pos, DUMMY_SP};
 use log::debug;
 
 pub struct DecodeContext<'a, 'tcx> {
@@ -344,7 +344,15 @@
         let hi = (hi + source_file.translated_source_file.start_pos)
                  - source_file.original_start_pos;
 
-        Ok(Span::new(lo, hi, NO_EXPANSION))
+        Ok(Span::with_root_ctxt(lo, hi))
+    }
+}
+
+impl SpecializedDecoder<Ident> for DecodeContext<'_, '_> {
+    fn specialized_decode(&mut self) -> Result<Ident, Self::Error> {
+        // FIXME(jseyfried): intercrate hygiene
+
+        Ok(Ident::with_dummy_span(Symbol::decode(self)?))
     }
 }
 
@@ -569,7 +577,7 @@
 
         ty::VariantDef::new(
             tcx,
-            Ident::with_empty_ctxt(self.item_name(index)),
+            Ident::with_dummy_span(self.item_name(index)),
             variant_did,
             ctor_did,
             data.discr,
@@ -577,7 +585,7 @@
                 let f = self.entry(index);
                 ty::FieldDef {
                     did: self.local_def_id(index),
-                    ident: Ident::with_empty_ctxt(self.item_name(index)),
+                    ident: Ident::with_dummy_span(self.item_name(index)),
                     vis: f.visibility.decode(self)
                 }
             }).collect(),
@@ -741,7 +749,7 @@
                         DefKind::Macro(ext.macro_kind()),
                         self.local_def_id(DefIndex::from_proc_macro_index(id)),
                     );
-                    let ident = Ident::with_empty_ctxt(name);
+                    let ident = Ident::with_dummy_span(name);
                     callback(def::Export {
                         ident: ident,
                         res: res,
@@ -783,7 +791,7 @@
                             if let Some(kind) = self.def_kind(child_index) {
                                 callback(def::Export {
                                     res: Res::Def(kind, self.local_def_id(child_index)),
-                                    ident: Ident::with_empty_ctxt(self.item_name(child_index)),
+                                    ident: Ident::with_dummy_span(self.item_name(child_index)),
                                     vis: self.get_visibility(child_index),
                                     span: self.entry(child_index).span.decode((self, sess)),
                                 });
diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
index fb675d7..e2de055 100644
--- a/src/librustc_metadata/encoder.rs
+++ b/src/librustc_metadata/encoder.rs
@@ -31,7 +31,7 @@
 use syntax::ast;
 use syntax::attr;
 use syntax::source_map::Spanned;
-use syntax::symbol::{kw, sym};
+use syntax::symbol::{kw, sym, Ident};
 use syntax_pos::{self, FileName, SourceFile, Span};
 use log::{debug, trace};
 
@@ -173,6 +173,13 @@
     }
 }
 
+impl SpecializedEncoder<Ident> for EncodeContext<'tcx> {
+    fn specialized_encode(&mut self, ident: &Ident) -> Result<(), Self::Error> {
+        // FIXME(jseyfried): intercrate hygiene
+        ident.name.encode(self)
+    }
+}
+
 impl<'tcx> SpecializedEncoder<LocalDefId> for EncodeContext<'tcx> {
     #[inline]
     fn specialized_encode(&mut self, def_id: &LocalDefId) -> Result<(), Self::Error> {
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index 70d6c15..9ff0c6c 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -272,12 +272,11 @@
 
     fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
         self.super_constant(constant, location);
-        self.sanitize_constant(constant, location);
-        self.sanitize_type(constant, constant.ty);
+        self.sanitize_type(constant, constant.literal.ty);
 
         if let Some(annotation_index) = constant.user_ty {
             if let Err(terr) = self.cx.relate_type_and_user_type(
-                constant.ty,
+                constant.literal.ty,
                 ty::Variance::Invariant,
                 &UserTypeProjection { base: annotation_index, projs: vec![], },
                 location.to_locations(),
@@ -289,7 +288,7 @@
                     constant,
                     "bad constant user type {:?} vs {:?}: {:?}",
                     annotation,
-                    constant.ty,
+                    constant.literal.ty,
                     terr,
                 );
             }
@@ -299,7 +298,7 @@
                     location.to_locations(),
                     ConstraintCategory::Boring,
                     self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
-                        constant.ty, def_id, UserSubsts { substs, user_self_ty: None },
+                        constant.literal.ty, def_id, UserSubsts { substs, user_self_ty: None },
                     )),
                 ) {
                     span_mirbug!(
@@ -403,41 +402,6 @@
         }
     }
 
-    /// Checks that the constant's `ty` field matches up with what would be
-    /// expected from its literal. Unevaluated constants and well-formed
-    /// constraints are checked by `visit_constant`.
-    fn sanitize_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
-        debug!(
-            "sanitize_constant(constant={:?}, location={:?})",
-            constant, location
-        );
-
-        let literal = constant.literal;
-
-        if let ConstValue::Unevaluated(..) = literal.val {
-            return;
-        }
-
-        debug!("sanitize_constant: expected_ty={:?}", literal.ty);
-
-        if let Err(terr) = self.cx.eq_types(
-            literal.ty,
-            constant.ty,
-            location.to_locations(),
-            ConstraintCategory::Boring,
-        ) {
-            span_mirbug!(
-                self,
-                constant,
-                "constant {:?} should have type {:?} but has {:?} ({:?})",
-                constant,
-                literal.ty,
-                constant.ty,
-                terr,
-            );
-        }
-    }
-
     /// Checks that the types internal to the `place` match up with
     /// what would be expected.
     fn sanitize_place(
diff --git a/src/librustc_mir/build/expr/as_constant.rs b/src/librustc_mir/build/expr/as_constant.rs
index 5197981..39bdc87 100644
--- a/src/librustc_mir/build/expr/as_constant.rs
+++ b/src/librustc_mir/build/expr/as_constant.rs
@@ -38,9 +38,9 @@
                         inferred_ty: ty,
                     })
                 });
+                assert_eq!(literal.ty, ty);
                 Constant {
                     span,
-                    ty,
                     user_ty,
                     literal,
                 }
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index ec061e7..1a186fa 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -591,7 +591,7 @@
         let n = (!0u128) >> (128 - bits);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);
 
-        self.literal_operand(span, ty, literal)
+        self.literal_operand(span, literal)
     }
 
     // Helper to get the minimum value of the appropriate type
@@ -602,6 +602,6 @@
         let n = 1 << (bits - 1);
         let literal = ty::Const::from_bits(self.hir.tcx(), n, param_ty);
 
-        self.literal_operand(span, ty, literal)
+        self.literal_operand(span, literal)
     }
 }
diff --git a/src/librustc_mir/build/expr/into.rs b/src/librustc_mir/build/expr/into.rs
index 02ab53f..889861b 100644
--- a/src/librustc_mir/build/expr/into.rs
+++ b/src/librustc_mir/build/expr/into.rs
@@ -114,7 +114,6 @@
                     destination,
                     Constant {
                         span: expr_span,
-                        ty: this.hir.bool_ty(),
                         user_ty: None,
                         literal: this.hir.true_literal(),
                     },
@@ -126,7 +125,6 @@
                     destination,
                     Constant {
                         span: expr_span,
-                        ty: this.hir.bool_ty(),
                         user_ty: None,
                         literal: this.hir.false_literal(),
                     },
diff --git a/src/librustc_mir/build/matches/simplify.rs b/src/librustc_mir/build/matches/simplify.rs
index d9b748f..3473155 100644
--- a/src/librustc_mir/build/matches/simplify.rs
+++ b/src/librustc_mir/build/matches/simplify.rs
@@ -108,8 +108,8 @@
                 Err(match_pair)
             }
 
-            PatternKind::Range(PatternRange { lo, hi, ty, end }) => {
-                let (range, bias) = match ty.sty {
+            PatternKind::Range(PatternRange { lo, hi, end }) => {
+                let (range, bias) = match lo.ty.sty {
                     ty::Char => {
                         (Some(('\u{0000}' as u128, '\u{10FFFF}' as u128, Size::from_bits(32))), 0)
                     }
diff --git a/src/librustc_mir/build/matches/test.rs b/src/librustc_mir/build/matches/test.rs
index 1c93abd..65e92d4 100644
--- a/src/librustc_mir/build/matches/test.rs
+++ b/src/librustc_mir/build/matches/test.rs
@@ -63,7 +63,8 @@
             }
 
             PatternKind::Range(range) => {
-                assert!(range.ty == match_pair.pattern.ty);
+                assert_eq!(range.lo.ty, match_pair.pattern.ty);
+                assert_eq!(range.hi.ty, match_pair.pattern.ty);
                 Test {
                     span: match_pair.pattern.span,
                     kind: TestKind::Range(range),
@@ -270,8 +271,9 @@
                     );
                 } else {
                     if let [success, fail] = *make_target_blocks(self) {
+                        assert_eq!(value.ty, ty);
+                        let expect = self.literal_operand(test.span, value);
                         let val = Operand::Copy(place.clone());
-                        let expect = self.literal_operand(test.span, ty, value);
                         self.compare(block, success, fail, source_info, BinOp::Eq, expect, val);
                     } else {
                         bug!("`TestKind::Eq` should have two target blocks");
@@ -279,13 +281,13 @@
                 }
             }
 
-            TestKind::Range(PatternRange { ref lo, ref hi, ty, ref end }) => {
+            TestKind::Range(PatternRange { ref lo, ref hi, ref end }) => {
                 let lower_bound_success = self.cfg.start_new_block();
                 let target_blocks = make_target_blocks(self);
 
                 // Test `val` by computing `lo <= val && val <= hi`, using primitive comparisons.
-                let lo = self.literal_operand(test.span, ty, lo);
-                let hi = self.literal_operand(test.span, ty, hi);
+                let lo = self.literal_operand(test.span, lo);
+                let hi = self.literal_operand(test.span, hi);
                 let val = Operand::Copy(place.clone());
 
                 if let [success, fail] = *target_blocks {
@@ -387,7 +389,7 @@
     ) {
         use rustc::middle::lang_items::EqTraitLangItem;
 
-        let mut expect = self.literal_operand(source_info.span, value.ty, value);
+        let mut expect = self.literal_operand(source_info.span, value);
         let mut val = Operand::Copy(place.clone());
 
         // If we're using `b"..."` as a pattern, we need to insert an
@@ -440,7 +442,7 @@
         };
 
         let eq_def_id = self.hir.tcx().require_lang_item(EqTraitLangItem);
-        let (mty, method) = self.hir.trait_method(eq_def_id, sym::eq, deref_ty, &[deref_ty.into()]);
+        let method = self.hir.trait_method(eq_def_id, sym::eq, deref_ty, &[deref_ty.into()]);
 
         let bool_ty = self.hir.bool_ty();
         let eq_result = self.temp(bool_ty, source_info.span);
@@ -449,7 +451,6 @@
         self.cfg.terminate(block, source_info, TerminatorKind::Call {
             func: Operand::Constant(box Constant {
                 span: source_info.span,
-                ty: mty,
 
                 // FIXME(#54571): This constant comes from user input (a
                 // constant in a pattern).  Are there forms where users can add
@@ -656,8 +657,9 @@
 
                     let tcx = self.hir.tcx();
 
-                    let lo = compare_const_vals(tcx, test.lo, pat.hi, self.hir.param_env, test.ty)?;
-                    let hi = compare_const_vals(tcx, test.hi, pat.lo, self.hir.param_env, test.ty)?;
+                    let test_ty = test.lo.ty;
+                    let lo = compare_const_vals(tcx, test.lo, pat.hi, self.hir.param_env, test_ty)?;
+                    let hi = compare_const_vals(tcx, test.hi, pat.lo, self.hir.param_env, test_ty)?;
 
                     match (test.end, pat.end, lo, hi) {
                         // pat < test
@@ -774,8 +776,8 @@
 
         let tcx = self.hir.tcx();
 
-        let a = compare_const_vals(tcx, range.lo, value, self.hir.param_env, range.ty)?;
-        let b = compare_const_vals(tcx, value, range.hi, self.hir.param_env, range.ty)?;
+        let a = compare_const_vals(tcx, range.lo, value, self.hir.param_env, range.lo.ty)?;
+        let b = compare_const_vals(tcx, value, range.hi, self.hir.param_env, range.lo.ty)?;
 
         match (b, range.end) {
             (Less, _) |
diff --git a/src/librustc_mir/build/misc.rs b/src/librustc_mir/build/misc.rs
index 56025ee..d038310 100644
--- a/src/librustc_mir/build/misc.rs
+++ b/src/librustc_mir/build/misc.rs
@@ -26,12 +26,10 @@
     /// without any user type annotation.
     pub fn literal_operand(&mut self,
                            span: Span,
-                           ty: Ty<'tcx>,
                            literal: &'tcx ty::Const<'tcx>)
                            -> Operand<'tcx> {
         let constant = box Constant {
             span,
-            ty,
             user_ty: None,
             literal,
         };
@@ -47,7 +45,7 @@
     pub fn zero_literal(&mut self, span: Span, ty: Ty<'tcx>) -> Operand<'tcx> {
         let literal = ty::Const::from_bits(self.hir.tcx(), 0, ty::ParamEnv::empty().and(ty));
 
-        self.literal_operand(span, ty, literal)
+        self.literal_operand(span, literal)
     }
 
     pub fn push_usize(&mut self,
@@ -61,7 +59,6 @@
             block, source_info, &temp,
             Constant {
                 span: source_info.span,
-                ty: self.hir.usize_ty(),
                 user_ty: None,
                 literal: self.hir.usize_literal(value),
             });
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index 1c6a743..a33d720 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -927,7 +927,7 @@
             ExprKind::Literal {
                 literal: cx.tcx.mk_const(ty::Const {
                     val: ConstValue::Unevaluated(def_id, substs),
-                    ty: cx.tcx.type_of(def_id),
+                    ty: cx.tables().node_type(expr.hir_id),
                 }),
                 user_ty,
             }
diff --git a/src/librustc_mir/hair/cx/mod.rs b/src/librustc_mir/hair/cx/mod.rs
index 3d9349d..740dc20 100644
--- a/src/librustc_mir/hair/cx/mod.rs
+++ b/src/librustc_mir/hair/cx/mod.rs
@@ -170,13 +170,13 @@
                         method_name: Symbol,
                         self_ty: Ty<'tcx>,
                         params: &[Kind<'tcx>])
-                        -> (Ty<'tcx>, &'tcx ty::Const<'tcx>) {
+                        -> &'tcx ty::Const<'tcx> {
         let substs = self.tcx.mk_substs_trait(self_ty, params);
         for item in self.tcx.associated_items(trait_def_id) {
             if item.kind == ty::AssocKind::Method && item.ident.name == method_name {
                 let method_ty = self.tcx.type_of(item.def_id);
                 let method_ty = method_ty.subst(self.tcx, substs);
-                return (method_ty, ty::Const::zero_sized(self.tcx, method_ty));
+                return ty::Const::zero_sized(self.tcx, method_ty);
             }
         }
 
diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs
index 8a3d904..1833ee3 100644
--- a/src/librustc_mir/hair/pattern/_match.rs
+++ b/src/librustc_mir/hair/pattern/_match.rs
@@ -609,7 +609,6 @@
                         ConstantRange(lo, hi, ty, end) => PatternKind::Range(PatternRange {
                             lo: ty::Const::from_bits(cx.tcx, lo, ty::ParamEnv::empty().and(ty)),
                             hi: ty::Const::from_bits(cx.tcx, hi, ty::ParamEnv::empty().and(ty)),
-                            ty,
                             end,
                         }),
                         _ => PatternKind::Wild,
@@ -880,10 +879,10 @@
         let range = loop {
             match pat.kind {
                 box PatternKind::Constant { value } => break ConstantValue(value),
-                box PatternKind::Range(PatternRange { lo, hi, ty, end }) => break ConstantRange(
-                    lo.eval_bits(tcx, param_env, ty),
-                    hi.eval_bits(tcx, param_env, ty),
-                    ty,
+                box PatternKind::Range(PatternRange { lo, hi, end }) => break ConstantRange(
+                    lo.eval_bits(tcx, param_env, lo.ty),
+                    hi.eval_bits(tcx, param_env, hi.ty),
+                    lo.ty,
                     end,
                 ),
                 box PatternKind::AscribeUserType { ref subpattern, .. } => {
@@ -1339,11 +1338,11 @@
             Some(vec![Variant(adt_def.variants[variant_index].def_id)])
         }
         PatternKind::Constant { value } => Some(vec![ConstantValue(value)]),
-        PatternKind::Range(PatternRange { lo, hi, ty, end }) =>
+        PatternKind::Range(PatternRange { lo, hi, end }) =>
             Some(vec![ConstantRange(
-                lo.eval_bits(cx.tcx, cx.param_env, ty),
-                hi.eval_bits(cx.tcx, cx.param_env, ty),
-                ty,
+                lo.eval_bits(cx.tcx, cx.param_env, lo.ty),
+                hi.eval_bits(cx.tcx, cx.param_env, hi.ty),
+                lo.ty,
                 end,
             )]),
         PatternKind::Array { .. } => match pcx.ty.sty {
@@ -1656,7 +1655,7 @@
 ) -> Result<bool, ErrorReported> {
     let (from, to, end, ty) = match pat.kind {
         box PatternKind::Constant { value } => (value, value, RangeEnd::Included, value.ty),
-        box PatternKind::Range(PatternRange { lo, hi, end, ty }) => (lo, hi, end, ty),
+        box PatternKind::Range(PatternRange { lo, hi, end }) => (lo, hi, end, lo.ty),
         _ => bug!("`constructor_covered_by_range` called with {:?}", pat),
     };
     trace!("constructor_covered_by_range {:#?}, {:#?}, {:#?}, {}", ctor, from, to, ty);
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index 1022315..bebb071 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -181,7 +181,6 @@
 pub struct PatternRange<'tcx> {
     pub lo: &'tcx ty::Const<'tcx>,
     pub hi: &'tcx ty::Const<'tcx>,
-    pub ty: Ty<'tcx>,
     pub end: RangeEnd,
 }
 
@@ -296,7 +295,7 @@
             PatternKind::Constant { value } => {
                 write!(f, "{}", value)
             }
-            PatternKind::Range(PatternRange { lo, hi, ty: _, end }) => {
+            PatternKind::Range(PatternRange { lo, hi, end }) => {
                 write!(f, "{}", lo)?;
                 match end {
                     RangeEnd::Included => write!(f, "..=")?,
@@ -442,6 +441,8 @@
 
                 let mut kind = match (lo, hi) {
                     (PatternKind::Constant { value: lo }, PatternKind::Constant { value: hi }) => {
+                        assert_eq!(lo.ty, ty);
+                        assert_eq!(hi.ty, ty);
                         let cmp = compare_const_vals(
                             self.tcx,
                             lo,
@@ -451,7 +452,7 @@
                         );
                         match (end, cmp) {
                             (RangeEnd::Excluded, Some(Ordering::Less)) =>
-                                PatternKind::Range(PatternRange { lo, hi, ty, end }),
+                                PatternKind::Range(PatternRange { lo, hi, end }),
                             (RangeEnd::Excluded, _) => {
                                 span_err!(
                                     self.tcx.sess,
@@ -465,7 +466,7 @@
                                 PatternKind::Constant { value: lo }
                             }
                             (RangeEnd::Included, Some(Ordering::Less)) => {
-                                PatternKind::Range(PatternRange { lo, hi, ty, end })
+                                PatternKind::Range(PatternRange { lo, hi, end })
                             }
                             (RangeEnd::Included, _) => {
                                 let mut err = struct_span_err!(
@@ -1416,17 +1417,7 @@
             } => PatternKind::Constant {
                 value,
             },
-            PatternKind::Range(PatternRange {
-                lo,
-                hi,
-                ty,
-                end,
-            }) => PatternKind::Range(PatternRange {
-                lo,
-                hi,
-                ty: ty.fold_with(folder),
-                end,
-            }),
+            PatternKind::Range(range) => PatternKind::Range(range),
             PatternKind::Slice {
                 ref prefix,
                 ref slice,
diff --git a/src/librustc_mir/interpret/intrinsics.rs b/src/librustc_mir/interpret/intrinsics.rs
index 89c5be1..ee105fe 100644
--- a/src/librustc_mir/interpret/intrinsics.rs
+++ b/src/librustc_mir/interpret/intrinsics.rs
@@ -110,18 +110,18 @@
                 };
                 self.write_scalar(out_val, dest)?;
             }
-            | "overflowing_add"
-            | "overflowing_sub"
-            | "overflowing_mul"
+            | "wrapping_add"
+            | "wrapping_sub"
+            | "wrapping_mul"
             | "add_with_overflow"
             | "sub_with_overflow"
             | "mul_with_overflow" => {
                 let lhs = self.read_immediate(args[0])?;
                 let rhs = self.read_immediate(args[1])?;
                 let (bin_op, ignore_overflow) = match intrinsic_name {
-                    "overflowing_add" => (BinOp::Add, true),
-                    "overflowing_sub" => (BinOp::Sub, true),
-                    "overflowing_mul" => (BinOp::Mul, true),
+                    "wrapping_add" => (BinOp::Add, true),
+                    "wrapping_sub" => (BinOp::Sub, true),
+                    "wrapping_mul" => (BinOp::Mul, true),
                     "add_with_overflow" => (BinOp::Add, false),
                     "sub_with_overflow" => (BinOp::Sub, false),
                     "mul_with_overflow" => (BinOp::Mul, false),
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index 33447eba..063e779 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -445,7 +445,6 @@
         let func_ty = tcx.mk_fn_def(self.def_id, substs);
         let func = Operand::Constant(box Constant {
             span: self.span,
-            ty: func_ty,
             user_ty: None,
             literal: ty::Const::zero_sized(tcx, func_ty),
         });
@@ -505,7 +504,6 @@
     fn make_usize(&self, value: u64) -> Box<Constant<'tcx>> {
         box Constant {
             span: self.span,
-            ty: self.tcx.types.usize,
             user_ty: None,
             literal: ty::Const::from_usize(self.tcx, value),
         }
@@ -745,7 +743,6 @@
             let ty = tcx.type_of(def_id);
             (Operand::Constant(box Constant {
                 span,
-                ty,
                 user_ty: None,
                 literal: ty::Const::zero_sized(tcx, ty),
              }),
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 38d26d0..c3c432d 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -539,7 +539,6 @@
         Operand::Constant(Box::new(
             Constant {
                 span,
-                ty,
                 user_ty: None,
                 literal: self.tcx.mk_const(*ty::Const::from_scalar(
                     self.tcx,
diff --git a/src/librustc_mir/transform/elaborate_drops.rs b/src/librustc_mir/transform/elaborate_drops.rs
index 0a021d9..4480d1e 100644
--- a/src/librustc_mir/transform/elaborate_drops.rs
+++ b/src/librustc_mir/transform/elaborate_drops.rs
@@ -527,7 +527,6 @@
     fn constant_bool(&self, span: Span, val: bool) -> Rvalue<'tcx> {
         Rvalue::Use(Operand::Constant(Box::new(Constant {
             span,
-            ty: self.tcx.types.bool,
             user_ty: None,
             literal: ty::Const::from_bool(self.tcx, val),
         })))
diff --git a/src/librustc_mir/transform/generator.rs b/src/librustc_mir/transform/generator.rs
index 94bb70e..f694188 100644
--- a/src/librustc_mir/transform/generator.rs
+++ b/src/librustc_mir/transform/generator.rs
@@ -975,7 +975,6 @@
     let term = TerminatorKind::Assert {
         cond: Operand::Constant(box Constant {
             span: body.span,
-            ty: tcx.types.bool,
             user_ty: None,
             literal: ty::Const::from_bool(tcx, false),
         }),
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index 40cb1fb..bc7bd39 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -328,7 +328,7 @@
                 }
 
                 TerminatorKind::Call {func: Operand::Constant(ref f), .. } => {
-                    if let ty::FnDef(def_id, _) = f.ty.sty {
+                    if let ty::FnDef(def_id, _) = f.literal.ty.sty {
                         // Don't give intrinsics the extra penalty for calls
                         let f = tcx.fn_sig(def_id);
                         if f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic {
diff --git a/src/librustc_mir/transform/instcombine.rs b/src/librustc_mir/transform/instcombine.rs
index 5542926..b2d063a 100644
--- a/src/librustc_mir/transform/instcombine.rs
+++ b/src/librustc_mir/transform/instcombine.rs
@@ -97,8 +97,7 @@
             let place_ty = place.ty(&self.body.local_decls, self.tcx).ty;
             if let ty::Array(_, len) = place_ty.sty {
                 let span = self.body.source_info(location).span;
-                let ty = self.tcx.types.usize;
-                let constant = Constant { span, ty, literal: len, user_ty: None };
+                let constant = Constant { span, literal: len, user_ty: None };
                 self.optimizations.arrays_lengths.insert(location, constant);
             }
         }
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index dcfc809..649cccc 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -249,7 +249,7 @@
                 if let ConstValue::Unevaluated(def_id, _) = constant.literal.val {
                     // Don't peek inside trait associated constants.
                     if cx.tcx.trait_of_item(def_id).is_some() {
-                        Self::in_any_value_of_ty(cx, constant.ty).unwrap_or(false)
+                        Self::in_any_value_of_ty(cx, constant.literal.ty).unwrap_or(false)
                     } else {
                         let (bits, _) = cx.tcx.at(constant.span).mir_const_qualif(def_id);
 
@@ -258,7 +258,7 @@
                         // Just in case the type is more specific than
                         // the definition, e.g., impl associated const
                         // with type parameters, take it into account.
-                        qualif && Self::mask_for_ty(cx, constant.ty)
+                        qualif && Self::mask_for_ty(cx, constant.literal.ty)
                     }
                 } else {
                     false
@@ -537,9 +537,9 @@
                             | "cttz_nonzero"
                             | "ctlz"
                             | "ctlz_nonzero"
-                            | "overflowing_add"
-                            | "overflowing_sub"
-                            | "overflowing_mul"
+                            | "wrapping_add"
+                            | "wrapping_sub"
+                            | "wrapping_mul"
                             | "unchecked_shl"
                             | "unchecked_shr"
                             | "rotate_left"
diff --git a/src/librustc_mir/transform/qualify_min_const_fn.rs b/src/librustc_mir/transform/qualify_min_const_fn.rs
index b84bc31..334d0ce 100644
--- a/src/librustc_mir/transform/qualify_min_const_fn.rs
+++ b/src/librustc_mir/transform/qualify_min_const_fn.rs
@@ -379,9 +379,9 @@
         | "add_with_overflow" // ~> .overflowing_add
         | "sub_with_overflow" // ~> .overflowing_sub
         | "mul_with_overflow" // ~> .overflowing_mul
-        | "overflowing_add" // ~> .wrapping_add
-        | "overflowing_sub" // ~> .wrapping_sub
-        | "overflowing_mul" // ~> .wrapping_mul
+        | "wrapping_add" // ~> .wrapping_add
+        | "wrapping_sub" // ~> .wrapping_sub
+        | "wrapping_mul" // ~> .wrapping_mul
         | "saturating_add" // ~> .saturating_add
         | "saturating_sub" // ~> .saturating_sub
         | "unchecked_shl" // ~> .wrapping_shl
diff --git a/src/librustc_mir/transform/rustc_peek.rs b/src/librustc_mir/transform/rustc_peek.rs
index 7fe8480..598de3a 100644
--- a/src/librustc_mir/transform/rustc_peek.rs
+++ b/src/librustc_mir/transform/rustc_peek.rs
@@ -224,7 +224,7 @@
     if let Some(mir::Terminator { ref kind, source_info, .. }) = *terminator {
         if let mir::TerminatorKind::Call { func: ref oper, ref args, .. } = *kind {
             if let mir::Operand::Constant(ref func) = *oper {
-                if let ty::FnDef(def_id, _) = func.ty.sty {
+                if let ty::FnDef(def_id, _) = func.literal.ty.sty {
                     let abi = tcx.fn_sig(def_id).abi();
                     let name = tcx.item_name(def_id);
                     if abi == Abi::RustIntrinsic && name == sym::rustc_peek {
diff --git a/src/librustc_mir/util/elaborate_drops.rs b/src/librustc_mir/util/elaborate_drops.rs
index 52fd645..c5561a1 100644
--- a/src/librustc_mir/util/elaborate_drops.rs
+++ b/src/librustc_mir/util/elaborate_drops.rs
@@ -970,7 +970,6 @@
     fn constant_usize(&self, val: u16) -> Operand<'tcx> {
         Operand::Constant(box Constant {
             span: self.source_info.span,
-            ty: self.tcx().types.usize,
             user_ty: None,
             literal: ty::Const::from_usize(self.tcx(), val.into()),
         })
diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
index 68880fc..ac27019 100644
--- a/src/librustc_mir/util/pretty.rs
+++ b/src/librustc_mir/util/pretty.rs
@@ -397,10 +397,9 @@
 impl Visitor<'tcx> for ExtraComments<'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
         self.super_constant(constant, location);
-        let Constant { span, ty, user_ty, literal } = constant;
+        let Constant { span, user_ty, literal } = constant;
         self.push("mir::Constant");
         self.push(&format!("+ span: {:?}", span));
-        self.push(&format!("+ ty: {:?}", ty));
         if let Some(user_ty) = user_ty {
             self.push(&format!("+ user_ty: {:?}", user_ty));
         }
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index 0a32b0c..1510d74 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -1,9 +1,11 @@
-//! Reduced graph building.
+//! After we obtain a fresh AST fragment from a macro, code in this module helps to integrate
+//! that fragment into the module structures that are already partially built.
 //!
-//! Here we build the "reduced graph": the graph of the module tree without
-//! any imports resolved.
+//! Items from the fragment are placed into modules,
+//! unexpanded macros in the fragment are visited and registered.
+//! Imports are also considered items and placed into modules here, but not resolved yet.
 
-use crate::macros::{InvocationData, LegacyBinding, LegacyScope};
+use crate::macros::{LegacyBinding, LegacyScope};
 use crate::resolve_imports::ImportDirective;
 use crate::resolve_imports::ImportDirectiveSubclass::{self, GlobImport, SingleImport};
 use crate::{Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
@@ -14,6 +16,7 @@
 use rustc::bug;
 use rustc::hir::def::{self, *};
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
+use rustc::hir::map::DefCollector;
 use rustc::ty;
 use rustc::middle::cstore::CrateStore;
 use rustc_metadata::cstore::LoadedMacro;
@@ -30,6 +33,7 @@
 use syntax::ast::{self, Block, ForeignItem, ForeignItemKind, Item, ItemKind, NodeId};
 use syntax::ast::{MetaItemKind, StmtKind, TraitItem, TraitItemKind, Variant};
 use syntax::ext::base::{MacroKind, SyntaxExtension};
+use syntax::ext::expand::AstFragment;
 use syntax::ext::hygiene::ExpnId;
 use syntax::feature_gate::is_builtin_attr;
 use syntax::parse::token::{self, Token};
@@ -67,7 +71,7 @@
     }
 }
 
-pub(crate) struct IsMacroExport;
+struct IsMacroExport;
 
 impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, ExpnId, IsMacroExport) {
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
@@ -84,7 +88,7 @@
 impl<'a> Resolver<'a> {
     /// Defines `name` in namespace `ns` of module `parent` to be `def` if it is not yet defined;
     /// otherwise, reports an error.
-    pub fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
+    crate fn define<T>(&mut self, parent: Module<'a>, ident: Ident, ns: Namespace, def: T)
         where T: ToNameBinding<'a>,
     {
         let binding = def.to_name_binding(self.arenas);
@@ -93,7 +97,7 @@
         }
     }
 
-    pub fn get_module(&mut self, def_id: DefId) -> Module<'a> {
+    crate fn get_module(&mut self, def_id: DefId) -> Module<'a> {
         if def_id.krate == LOCAL_CRATE {
             return self.module_map[&def_id]
         }
@@ -119,7 +123,7 @@
         module
     }
 
-    pub fn macro_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
+    crate fn macro_def_scope(&mut self, expn_id: ExpnId) -> Module<'a> {
         let def_id = match self.macro_defs.get(&expn_id) {
             Some(def_id) => *def_id,
             None => return self.graph_root,
@@ -141,7 +145,7 @@
         }
     }
 
-    crate fn get_macro_by_def_id(&mut self, def_id: DefId) -> Option<Lrc<SyntaxExtension>> {
+    fn get_macro_by_def_id(&mut self, def_id: DefId) -> Option<Lrc<SyntaxExtension>> {
         if let Some(ext) = self.macro_map.get(&def_id) {
             return Some(ext.clone());
         }
@@ -156,23 +160,32 @@
         Some(ext)
     }
 
-    /// Ensures that the reduced graph rooted at the given external module
-    /// is built, building it if it is not.
-    pub fn populate_module_if_necessary(&mut self, module: Module<'a>) {
-        if module.populated.get() { return }
-        let def_id = module.def_id().unwrap();
+    crate fn build_reduced_graph(
+        &mut self, fragment: &AstFragment, parent_scope: ParentScope<'a>
+    ) -> LegacyScope<'a> {
+        fragment.visit_with(&mut DefCollector::new(&mut self.definitions, parent_scope.expansion));
+        let mut visitor = BuildReducedGraphVisitor { r: self, parent_scope };
+        fragment.visit_with(&mut visitor);
+        visitor.parent_scope.legacy
+    }
+
+    crate fn build_reduced_graph_external(&mut self, module: Module<'a>) {
+        let def_id = module.def_id().expect("unpopulated module without a def-id");
         for child in self.cstore.item_children_untracked(def_id, self.session) {
             let child = child.map_id(|_| panic!("unexpected id"));
-            BuildReducedGraphVisitor { parent_scope: self.dummy_parent_scope(), r: self }
-                .build_reduced_graph_for_external_crate_res(module, child);
+            BuildReducedGraphVisitor { r: self, parent_scope: ParentScope::module(module) }
+                .build_reduced_graph_for_external_crate_res(child);
         }
-        module.populated.set(true)
     }
 }
 
-pub struct BuildReducedGraphVisitor<'a, 'b> {
-    pub r: &'b mut Resolver<'a>,
-    pub parent_scope: ParentScope<'a>,
+struct BuildReducedGraphVisitor<'a, 'b> {
+    r: &'b mut Resolver<'a>,
+    parent_scope: ParentScope<'a>,
+}
+
+impl<'a> AsMut<Resolver<'a>> for BuildReducedGraphVisitor<'a, '_> {
+    fn as_mut(&mut self) -> &mut Resolver<'a> { self.r }
 }
 
 impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
@@ -300,10 +313,9 @@
         root_id: NodeId,
         vis: ty::Visibility,
     ) {
-        let parent_scope = &self.parent_scope;
-        let current_module = parent_scope.module;
+        let current_module = self.parent_scope.module;
         let directive = self.r.arenas.alloc_import_directive(ImportDirective {
-            parent_scope: parent_scope.clone(),
+            parent_scope: self.parent_scope,
             module_path,
             imported_module: Cell::new(None),
             subclass,
@@ -593,15 +605,13 @@
                     self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
                 };
 
-                self.r.populate_module_if_necessary(module);
-
                 let used = self.process_legacy_macro_imports(item, module);
                 let binding =
                     (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
                 let directive = self.r.arenas.alloc_import_directive(ImportDirective {
                     root_id: item.id,
                     id: item.id,
-                    parent_scope: self.parent_scope.clone(),
+                    parent_scope: self.parent_scope,
                     imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
                     subclass: ImportDirectiveSubclass::ExternCrate {
                         source: orig_name,
@@ -706,7 +716,7 @@
                 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
 
                 for variant in &(*enum_definition).variants {
-                    self.build_reduced_graph_for_variant(variant, module, vis, expansion);
+                    self.build_reduced_graph_for_variant(variant, module, vis);
                 }
             }
 
@@ -797,8 +807,8 @@
     fn build_reduced_graph_for_variant(&mut self,
                                        variant: &Variant,
                                        parent: Module<'a>,
-                                       vis: ty::Visibility,
-                                       expn_id: ExpnId) {
+                                       vis: ty::Visibility) {
+        let expn_id = self.parent_scope.expansion;
         let ident = variant.ident;
 
         // Define a name in the type namespace.
@@ -861,20 +871,19 @@
     }
 
     /// Builds the reduced graph for a single item in an external crate.
-    fn build_reduced_graph_for_external_crate_res(
-        &mut self,
-        parent: Module<'a>,
-        child: Export<ast::NodeId>,
-    ) {
+    fn build_reduced_graph_for_external_crate_res(&mut self, child: Export<ast::NodeId>) {
+        let parent = self.parent_scope.module;
         let Export { ident, res, vis, span } = child;
         // FIXME: We shouldn't create the gensym here, it should come from metadata,
         // but metadata cannot encode gensyms currently, so we create it here.
         // This is only a guess, two equivalent idents may incorrectly get different gensyms here.
         let ident = ident.gensym_if_underscore();
         let expansion = ExpnId::root(); // FIXME(jseyfried) intercrate hygiene
+        // Record primary definitions.
         match res {
             Res::Def(kind @ DefKind::Mod, def_id)
-            | Res::Def(kind @ DefKind::Enum, def_id) => {
+            | Res::Def(kind @ DefKind::Enum, def_id)
+            | Res::Def(kind @ DefKind::Trait, def_id) => {
                 let module = self.r.new_module(parent,
                                              ModuleKind::Def(kind, def_id, ident.name),
                                              def_id,
@@ -882,70 +891,55 @@
                                              span);
                 self.r.define(parent, ident, TypeNS, (module, vis, DUMMY_SP, expansion));
             }
-            Res::Def(DefKind::Variant, _)
+            Res::Def(DefKind::Struct, _)
+            | Res::Def(DefKind::Union, _)
+            | Res::Def(DefKind::Variant, _)
             | Res::Def(DefKind::TyAlias, _)
             | Res::Def(DefKind::ForeignTy, _)
             | Res::Def(DefKind::OpaqueTy, _)
             | Res::Def(DefKind::TraitAlias, _)
+            | Res::Def(DefKind::AssocTy, _)
+            | Res::Def(DefKind::AssocOpaqueTy, _)
             | Res::PrimTy(..)
-            | Res::ToolMod => {
-                self.r.define(parent, ident, TypeNS, (res, vis, DUMMY_SP, expansion));
-            }
+            | Res::ToolMod =>
+                self.r.define(parent, ident, TypeNS, (res, vis, DUMMY_SP, expansion)),
             Res::Def(DefKind::Fn, _)
+            | Res::Def(DefKind::Method, _)
             | Res::Def(DefKind::Static, _)
             | Res::Def(DefKind::Const, _)
-            | Res::Def(DefKind::Ctor(CtorOf::Variant, ..), _) => {
-                self.r.define(parent, ident, ValueNS, (res, vis, DUMMY_SP, expansion));
-            }
-            Res::Def(DefKind::Ctor(CtorOf::Struct, ..), def_id) => {
-                self.r.define(parent, ident, ValueNS, (res, vis, DUMMY_SP, expansion));
-
-                if let Some(struct_def_id) =
-                        self.r.cstore.def_key(def_id).parent
-                            .map(|index| DefId { krate: def_id.krate, index: index }) {
-                    self.r.struct_constructors.insert(struct_def_id, (res, vis));
-                }
-            }
-            Res::Def(DefKind::Trait, def_id) => {
-                let module_kind = ModuleKind::Def(DefKind::Trait, def_id, ident.name);
-                let module = self.r.new_module(parent,
-                                             module_kind,
-                                             parent.normal_ancestor_id,
-                                             expansion,
-                                             span);
-                self.r.define(parent, ident, TypeNS, (module, vis, DUMMY_SP, expansion));
-
-                for child in self.r.cstore.item_children_untracked(def_id, self.r.session) {
-                    let res = child.res.map_id(|_| panic!("unexpected id"));
-                    let ns = if let Res::Def(DefKind::AssocTy, _) = res {
-                        TypeNS
-                    } else { ValueNS };
-                    self.r.define(module, child.ident, ns,
-                                (res, ty::Visibility::Public, DUMMY_SP, expansion));
-
-                    if self.r.cstore.associated_item_cloned_untracked(child.res.def_id())
-                           .method_has_self_argument {
-                        self.r.has_self.insert(res.def_id());
-                    }
-                }
-                module.populated.set(true);
-            }
+            | Res::Def(DefKind::AssocConst, _)
+            | Res::Def(DefKind::Ctor(..), _) =>
+                self.r.define(parent, ident, ValueNS, (res, vis, DUMMY_SP, expansion)),
+            Res::Def(DefKind::Macro(..), _)
+            | Res::NonMacroAttr(..) =>
+                self.r.define(parent, ident, MacroNS, (res, vis, DUMMY_SP, expansion)),
+            Res::Def(DefKind::TyParam, _) | Res::Def(DefKind::ConstParam, _)
+            | Res::Local(..) | Res::SelfTy(..) | Res::SelfCtor(..) | Res::Err =>
+                bug!("unexpected resolution: {:?}", res)
+        }
+        // Record some extra data for better diagnostics.
+        match res {
             Res::Def(DefKind::Struct, def_id) | Res::Def(DefKind::Union, def_id) => {
-                self.r.define(parent, ident, TypeNS, (res, vis, DUMMY_SP, expansion));
-
-                // Record field names for error reporting.
                 let field_names = self.r.cstore.struct_field_names_untracked(def_id);
                 self.insert_field_names(def_id, field_names);
             }
-            Res::Def(DefKind::Macro(..), _) | Res::NonMacroAttr(..) => {
-                self.r.define(parent, ident, MacroNS, (res, vis, DUMMY_SP, expansion));
+            Res::Def(DefKind::Method, def_id) => {
+                if self.r.cstore.associated_item_cloned_untracked(def_id).method_has_self_argument {
+                    self.r.has_self.insert(def_id);
+                }
             }
-            _ => bug!("unexpected resolution: {:?}", res)
+            Res::Def(DefKind::Ctor(CtorOf::Struct, ..), def_id) => {
+                let parent = self.r.cstore.def_key(def_id).parent;
+                if let Some(struct_def_id) = parent.map(|index| DefId { index, ..def_id }) {
+                    self.r.struct_constructors.insert(struct_def_id, (res, vis));
+                }
+            }
+            _ => {}
         }
     }
 
     fn legacy_import_macro(&mut self,
-                           name: Name,
+                           name: ast::Name,
                            binding: &'a NameBinding<'a>,
                            span: Span,
                            allow_shadowing: bool) {
@@ -997,7 +991,7 @@
                 |this: &Self, span| this.r.arenas.alloc_import_directive(ImportDirective {
             root_id: item.id,
             id: item.id,
-            parent_scope: this.parent_scope.clone(),
+            parent_scope: this.parent_scope,
             imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
             subclass: ImportDirectiveSubclass::MacroUse,
             use_span_with_attributes: item.span_with_attributes(),
@@ -1014,9 +1008,9 @@
         if let Some(span) = import_all {
             let directive = macro_use_directive(self, span);
             self.r.potentially_unused_imports.push(directive);
-            module.for_each_child(|ident, ns, binding| if ns == MacroNS {
-                let imported_binding = self.r.import(binding, directive);
-                self.legacy_import_macro(ident.name, imported_binding, span, allow_shadowing);
+            module.for_each_child(self, |this, ident, ns, binding| if ns == MacroNS {
+                let imported_binding = this.r.import(binding, directive);
+                this.legacy_import_macro(ident.name, imported_binding, span, allow_shadowing);
             });
         } else {
             for ident in single_imports.iter().cloned() {
@@ -1066,20 +1060,15 @@
         false
     }
 
-    fn visit_invoc(&mut self, id: ast::NodeId) -> &'a InvocationData<'a> {
+    fn visit_invoc(&mut self, id: ast::NodeId) -> LegacyScope<'a> {
         let invoc_id = id.placeholder_to_expn_id();
 
         self.parent_scope.module.unresolved_invocations.borrow_mut().insert(invoc_id);
 
-        let invocation_data = self.r.arenas.alloc_invocation_data(InvocationData {
-            module: self.parent_scope.module,
-            parent_legacy_scope: self.parent_scope.legacy,
-            output_legacy_scope: Cell::new(None),
-        });
-        let old_invocation_data = self.r.invocations.insert(invoc_id, invocation_data);
-        assert!(old_invocation_data.is_none(), "invocation data is reset for an invocation");
+        let old_parent_scope = self.r.invocation_parent_scopes.insert(invoc_id, self.parent_scope);
+        assert!(old_parent_scope.is_none(), "invocation data is reset for an invocation");
 
-        invocation_data
+        LegacyScope::Invocation(invoc_id)
     }
 
     fn proc_macro_stub(item: &ast::Item) -> Option<(MacroKind, Ident, Span)> {
@@ -1180,7 +1169,7 @@
                 return
             }
             ItemKind::Mac(..) => {
-                self.parent_scope.legacy = LegacyScope::Invocation(self.visit_invoc(item.id));
+                self.parent_scope.legacy = self.visit_invoc(item.id);
                 return
             }
             ItemKind::Mod(..) => self.contains_macro_use(&item.attrs),
@@ -1199,7 +1188,7 @@
 
     fn visit_stmt(&mut self, stmt: &'b ast::Stmt) {
         if let ast::StmtKind::Mac(..) = stmt.node {
-            self.parent_scope.legacy = LegacyScope::Invocation(self.visit_invoc(stmt.id));
+            self.parent_scope.legacy = self.visit_invoc(stmt.id);
         } else {
             visit::walk_stmt(self, stmt);
         }
@@ -1267,9 +1256,7 @@
 
     fn visit_attribute(&mut self, attr: &'b ast::Attribute) {
         if !attr.is_sugared_doc && is_builtin_attr(attr) {
-            self.parent_scope.module.builtin_attrs.borrow_mut().push((
-                attr.path.segments[0].ident, self.parent_scope.clone()
-            ));
+            self.r.builtin_attrs.push((attr.path.segments[0].ident, self.parent_scope));
         }
         visit::walk_attribute(self, attr);
     }
diff --git a/src/librustc_resolve/diagnostics.rs b/src/librustc_resolve/diagnostics.rs
index 1de67ed..b79e0c2 100644
--- a/src/librustc_resolve/diagnostics.rs
+++ b/src/librustc_resolve/diagnostics.rs
@@ -73,20 +73,23 @@
     false
 }
 
-crate fn add_module_candidates(
-    module: Module<'_>, names: &mut Vec<TypoSuggestion>, filter_fn: &impl Fn(Res) -> bool
-) {
-    for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
-        if let Some(binding) = resolution.borrow().binding {
-            let res = binding.res();
-            if filter_fn(res) {
-                names.push(TypoSuggestion::from_res(ident.name, res));
+impl<'a> Resolver<'a> {
+    crate fn add_module_candidates(
+        &mut self,
+        module: Module<'a>,
+        names: &mut Vec<TypoSuggestion>,
+        filter_fn: &impl Fn(Res) -> bool,
+    ) {
+        for (&(ident, _), resolution) in self.resolutions(module).borrow().iter() {
+            if let Some(binding) = resolution.borrow().binding {
+                let res = binding.res();
+                if filter_fn(res) {
+                    names.push(TypoSuggestion::from_res(ident.name, res));
+                }
             }
         }
     }
-}
 
-impl<'a> Resolver<'a> {
     /// Combines an error with provided span and emits it.
     ///
     /// This takes the error provided, combines it with the span and any additional spans inside the
@@ -166,12 +169,14 @@
                 err
             }
             ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
-                let mut err = struct_span_err!(self.session,
-                                                span,
-                                                E0403,
-                                                "the name `{}` is already used for a generic \
-                                                parameter in this list of generic parameters",
-                                                name);
+                let mut err = struct_span_err!(
+                    self.session,
+                    span,
+                    E0403,
+                    "the name `{}` is already used for a generic \
+                     parameter in this item's generic parameters",
+                    name,
+                );
                 err.span_label(span, "already used");
                 err.span_label(first_use_span, format!("first use of `{}`", name));
                 err
@@ -376,9 +381,9 @@
                 Scope::DeriveHelpers => {
                     let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
                     if filter_fn(res) {
-                        for derive in &parent_scope.derives {
+                        for derive in parent_scope.derives {
                             let parent_scope =
-                                &ParentScope { derives: Vec::new(), ..*parent_scope };
+                                &ParentScope { derives: &[], ..*parent_scope };
                             if let Ok((Some(ext), _)) = this.resolve_macro_path(
                                 derive, Some(MacroKind::Derive), parent_scope, false, false
                             ) {
@@ -402,10 +407,10 @@
                 Scope::CrateRoot => {
                     let root_ident = Ident::new(kw::PathRoot, ident.span);
                     let root_module = this.resolve_crate_root(root_ident);
-                    add_module_candidates(root_module, &mut suggestions, filter_fn);
+                    this.add_module_candidates(root_module, &mut suggestions, filter_fn);
                 }
                 Scope::Module(module) => {
-                    add_module_candidates(module, &mut suggestions, filter_fn);
+                    this.add_module_candidates(module, &mut suggestions, filter_fn);
                 }
                 Scope::MacroUsePrelude => {
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(|(name, binding)| {
@@ -453,9 +458,9 @@
                 Scope::StdLibPrelude => {
                     if let Some(prelude) = this.prelude {
                         let mut tmp_suggestions = Vec::new();
-                        add_module_candidates(prelude, &mut tmp_suggestions, filter_fn);
+                        this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn);
                         suggestions.extend(tmp_suggestions.into_iter().filter(|s| {
-                            use_prelude || this.is_builtin_macro(s.res.opt_def_id())
+                            use_prelude || this.is_builtin_macro(s.res)
                         }));
                     }
                 }
@@ -509,11 +514,9 @@
         while let Some((in_module,
                         path_segments,
                         in_module_is_extern)) = worklist.pop() {
-            self.populate_module_if_necessary(in_module);
-
             // We have to visit module children in deterministic order to avoid
             // instabilities in reported imports (#43552).
-            in_module.for_each_child_stable(|ident, ns, name_binding| {
+            in_module.for_each_child_stable(self, |this, ident, ns, name_binding| {
                 // avoid imports entirely
                 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
                 // avoid non-importable candidates as well
@@ -547,7 +550,7 @@
                         // outside crate private modules => no need to check this)
                         if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
                             let did = match res {
-                                Res::Def(DefKind::Ctor(..), did) => self.parent(did),
+                                Res::Def(DefKind::Ctor(..), did) => this.parent(did),
                                 _ => res.opt_def_id(),
                             };
                             candidates.push(ImportSuggestion { did, path });
@@ -595,7 +598,7 @@
         where FilterFn: Fn(Res) -> bool
     {
         let mut suggestions = self.lookup_import_candidates_from_module(
-            lookup_ident, namespace, self.graph_root, Ident::with_empty_ctxt(kw::Crate), &filter_fn
+            lookup_ident, namespace, self.graph_root, Ident::with_dummy_span(kw::Crate), &filter_fn
         );
 
         if lookup_ident.span.rust_2018() {
@@ -607,8 +610,6 @@
                         krate: crate_id,
                         index: CRATE_DEF_INDEX,
                     });
-                    self.populate_module_if_necessary(&crate_root);
-
                     suggestions.extend(self.lookup_import_candidates_from_module(
                         lookup_ident, namespace, crate_root, ident, &filter_fn));
                 }
@@ -805,7 +806,7 @@
     ///            at the root of the crate instead of the module where it is defined
     /// ```
     pub(crate) fn check_for_module_export_macro(
-        &self,
+        &mut self,
         directive: &'b ImportDirective<'b>,
         module: ModuleOrUniformRoot<'b>,
         ident: Ident,
@@ -826,7 +827,7 @@
             return None;
         }
 
-        let resolutions = crate_module.resolutions.borrow();
+        let resolutions = self.r.resolutions(crate_module).borrow();
         let resolution = resolutions.get(&(ident, MacroNS))?;
         let binding = resolution.borrow().binding()?;
         if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() {
diff --git a/src/librustc_resolve/error_codes.rs b/src/librustc_resolve/error_codes.rs
index e01f537..1faaf97 100644
--- a/src/librustc_resolve/error_codes.rs
+++ b/src/librustc_resolve/error_codes.rs
@@ -526,15 +526,25 @@
 Erroneous code example:
 
 ```compile_fail,E0403
-fn foo<T, T>(s: T, u: T) {} // error: the name `T` is already used for a type
-                            //        parameter in this type parameter list
+fn f<T, T>(s: T, u: T) {} // error: the name `T` is already used for a generic
+                          //        parameter in this item's generic parameters
 ```
 
 Please verify that none of the type parameters are misspelled, and rename any
 clashing parameters. Example:
 
 ```
-fn foo<T, Y>(s: T, u: Y) {} // ok!
+fn f<T, Y>(s: T, u: Y) {} // ok!
+```
+
+Type parameters in an associated item also cannot shadow parameters from the
+containing item:
+
+```compile_fail,E0403
+trait Foo<T> {
+    fn do_something(&self) -> T;
+    fn do_something_else<T: Clone>(&self, bar: T);
+}
 ```
 "##,
 
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index 358eaae..e15d02a 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -1,3 +1,10 @@
+//! "Late resolution" is the pass that resolves most of names in a crate beside imports and macros.
+//! It runs when the crate is fully expanded and its module structure is fully built.
+//! So it just walks through the crate and resolves all the expressions, types, etc.
+//!
+//! If you wonder why there's no `early.rs`, that's because it's split into three files -
+//! `build_reduced_graph.rs`, `macros.rs` and `resolve_imports.rs`.
+
 use GenericParameters::*;
 use RibKind::*;
 
@@ -104,6 +111,24 @@
     TyParamAsConstParamTy,
 }
 
+impl RibKind<'_> {
+    // Whether this rib kind contains generic parameters, as opposed to local
+    // variables.
+    crate fn contains_params(&self) -> bool {
+        match self {
+            NormalRibKind
+            | FnItemRibKind
+            | ConstantItemRibKind
+            | ModuleRibKind(_)
+            | MacroDefinition(_) => false,
+            AssocItemRibKind
+            | ItemRibKind
+            | ForwardTyParamBanRibKind
+            | TyParamAsConstParamTy => true,
+        }
+    }
+}
+
 /// A single local scope.
 ///
 /// A rib represents a scope names can live in. Note that these appear in many places, not just
@@ -352,7 +377,7 @@
                 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
             }
             TyKind::ImplicitSelf => {
-                let self_ty = Ident::with_empty_ctxt(kw::SelfUpper);
+                let self_ty = Ident::with_dummy_span(kw::SelfUpper);
                 let res = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
                               .map_or(Res::Err, |d| d.res());
                 self.r.record_partial_res(ty.id, PartialRes::new(res));
@@ -442,7 +467,7 @@
                 GenericParamKind::Type { ref default, .. } => {
                     found_default |= default.is_some();
                     if found_default {
-                        Some((Ident::with_empty_ctxt(param.ident.name), Res::Err))
+                        Some((Ident::with_dummy_span(param.ident.name), Res::Err))
                     } else {
                         None
                     }
@@ -459,7 +484,7 @@
                     false
                 }
             })
-            .map(|param| (Ident::with_empty_ctxt(param.ident.name), Res::Err)));
+            .map(|param| (Ident::with_dummy_span(param.ident.name), Res::Err)));
 
         for param in &generics.params {
             match param.kind {
@@ -476,7 +501,7 @@
                     }
 
                     // Allow all following defaults to refer to this type parameter.
-                    default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
+                    default_ban_rib.bindings.remove(&Ident::with_dummy_span(param.ident.name));
                 }
                 GenericParamKind::Const { ref ty } => {
                     self.ribs[TypeNS].push(const_ty_param_ban_rib);
@@ -501,8 +526,8 @@
     fn new(resolver: &'b mut Resolver<'a>) -> LateResolutionVisitor<'a, 'b> {
         // During late resolution we only track the module component of the parent scope,
         // although it may be useful to track other components as well for diagnostics.
-        let parent_scope = resolver.dummy_parent_scope();
         let graph_root = resolver.graph_root;
+        let parent_scope = ParentScope::module(graph_root);
         LateResolutionVisitor {
             r: resolver,
             parent_scope,
@@ -574,7 +599,6 @@
             self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
             self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
 
-            self.r.finalize_current_module_macro_resolutions(module);
             let ret = f(self);
 
             self.parent_scope.module = orig_module;
@@ -792,6 +816,19 @@
                 let mut function_type_rib = Rib::new(rib_kind);
                 let mut function_value_rib = Rib::new(rib_kind);
                 let mut seen_bindings = FxHashMap::default();
+                // We also can't shadow bindings from the parent item
+                if let AssocItemRibKind = rib_kind {
+                    let mut add_bindings_for_ns = |ns| {
+                        let parent_rib = self.ribs[ns].iter()
+                            .rfind(|rib| if let ItemRibKind = rib.kind { true } else { false })
+                            .expect("associated item outside of an item");
+                        seen_bindings.extend(
+                            parent_rib.bindings.iter().map(|(ident, _)| (*ident, ident.span)),
+                        );
+                    };
+                    add_bindings_for_ns(ValueNS);
+                    add_bindings_for_ns(TypeNS);
+                }
                 for param in &generics.params {
                     match param.kind {
                         GenericParamKind::Lifetime { .. } => {}
@@ -965,7 +1002,7 @@
         let mut self_type_rib = Rib::new(NormalRibKind);
 
         // Plain insert (no renaming, since types are not currently hygienic)
-        self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
+        self_type_rib.bindings.insert(Ident::with_dummy_span(kw::SelfUpper), self_res);
         self.ribs[TypeNS].push(self_type_rib);
         f(self);
         self.ribs[TypeNS].pop();
@@ -976,7 +1013,7 @@
     {
         let self_res = Res::SelfCtor(impl_id);
         let mut self_type_rib = Rib::new(NormalRibKind);
-        self_type_rib.bindings.insert(Ident::with_empty_ctxt(kw::SelfUpper), self_res);
+        self_type_rib.bindings.insert(Ident::with_dummy_span(kw::SelfUpper), self_res);
         self.ribs[ValueNS].push(self_type_rib);
         f(self);
         self.ribs[ValueNS].pop();
@@ -1227,7 +1264,6 @@
             self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
             self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
             self.parent_scope.module = anonymous_module;
-            self.r.finalize_current_module_macro_resolutions(anonymous_module);
         } else {
             self.ribs[ValueNS].push(Rib::new(NormalRibKind));
         }
@@ -1476,7 +1512,7 @@
                     self.r.trait_map.insert(id, traits);
                 }
 
-                let mut std_path = vec![Segment::from_ident(Ident::with_empty_ctxt(sym::std))];
+                let mut std_path = vec![Segment::from_ident(Ident::with_dummy_span(sym::std))];
                 std_path.extend(path);
                 if self.r.primitive_type_table.primitive_types.contains_key(&path[0].ident.name) {
                     let cl = CrateLint::No;
@@ -1507,7 +1543,7 @@
 
     fn self_type_is_available(&mut self, span: Span) -> bool {
         let binding = self.resolve_ident_in_lexical_scope(
-            Ident::with_empty_ctxt(kw::SelfUpper),
+            Ident::with_dummy_span(kw::SelfUpper),
             TypeNS,
             None,
             span,
@@ -1924,7 +1960,7 @@
         let mut traits = module.traits.borrow_mut();
         if traits.is_none() {
             let mut collected_traits = Vec::new();
-            module.for_each_child(|name, ns, binding| {
+            module.for_each_child(self.r, |_, name, ns, binding| {
                 if ns != TypeNS { return }
                 match binding.res() {
                     Res::Def(DefKind::Trait, _) |
@@ -1984,7 +2020,6 @@
 
 impl<'a> Resolver<'a> {
     pub(crate) fn late_resolve_crate(&mut self, krate: &Crate) {
-        self.finalize_current_module_macro_resolutions(self.graph_root);
         let mut late_resolution_visitor = LateResolutionVisitor::new(self);
         visit::walk_crate(&mut late_resolution_visitor, krate);
         for (id, span) in late_resolution_visitor.unused_labels.iter() {
diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index 68f9c16..a822fa0 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -1,8 +1,7 @@
 use crate::{CrateLint, Module, ModuleKind, ModuleOrUniformRoot};
 use crate::{PathResult, PathSource, Segment};
 use crate::path_names_to_string;
-use crate::diagnostics::{add_typo_suggestion, add_module_candidates};
-use crate::diagnostics::{ImportSuggestion, TypoSuggestion};
+use crate::diagnostics::{add_typo_suggestion, ImportSuggestion, TypoSuggestion};
 use crate::late::{LateResolutionVisitor, RibKind};
 
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
@@ -548,7 +547,7 @@
                 // Items in scope
                 if let RibKind::ModuleRibKind(module) = rib.kind {
                     // Items from this module
-                    add_module_candidates(module, &mut names, &filter_fn);
+                    self.r.add_module_candidates(module, &mut names, &filter_fn);
 
                     if let ModuleKind::Block(..) = module.kind {
                         // We can see through blocks
@@ -577,7 +576,7 @@
                             }));
 
                             if let Some(prelude) = self.r.prelude {
-                                add_module_candidates(prelude, &mut names, &filter_fn);
+                                self.r.add_module_candidates(prelude, &mut names, &filter_fn);
                             }
                         }
                         break;
@@ -599,7 +598,7 @@
                 mod_path, Some(TypeNS), false, span, CrateLint::No
             ) {
                 if let ModuleOrUniformRoot::Module(module) = module {
-                    add_module_candidates(module, &mut names, &filter_fn);
+                    self.r.add_module_candidates(module, &mut names, &filter_fn);
                 }
             }
         }
@@ -717,9 +716,7 @@
             // abort if the module is already found
             if result.is_some() { break; }
 
-            self.r.populate_module_if_necessary(in_module);
-
-            in_module.for_each_child_stable(|ident, _, name_binding| {
+            in_module.for_each_child_stable(self.r, |_, ident, _, name_binding| {
                 // abort if the module is already found or if name_binding is private external
                 if result.is_some() || !name_binding.vis.is_visible_locally() {
                     return
@@ -750,10 +747,8 @@
 
     fn collect_enum_variants(&mut self, def_id: DefId) -> Option<Vec<Path>> {
         self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
-            self.r.populate_module_if_necessary(enum_module);
-
             let mut variants = Vec::new();
-            enum_module.for_each_child_stable(|ident, _, name_binding| {
+            enum_module.for_each_child_stable(self.r, |_, ident, _, name_binding| {
                 if let Res::Def(DefKind::Variant, _) = name_binding.res() {
                     let mut segms = enum_import_suggestion.path.segments.clone();
                     segms.push(ast::PathSegment::from_ident(ident));
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 8a4a60c..984473d 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -1,3 +1,12 @@
+//! This crate is responsible for the part of name resolution that doesn't require type checker.
+//!
+//! Module structure of the crate is built here.
+//! Paths in macros, imports, expressions, types, patterns are resolved here.
+//! Label names are resolved here as well.
+//!
+//! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
+//! Lifetime names are resolved in `librustc/middle/resolve_lifetime.rs`.
+
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(crate_visibility_modifier)]
@@ -54,7 +63,7 @@
 use diagnostics::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
 use late::{PathSource, Rib, RibKind::*};
 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
-use macros::{InvocationData, LegacyBinding, LegacyScope};
+use macros::{LegacyBinding, LegacyScope};
 
 type Res = def::Res<NodeId>;
 
@@ -122,12 +131,25 @@
 /// Serves as a starting point for the scope visitor.
 /// This struct is currently used only for early resolution (imports and macros),
 /// but not for late resolution yet.
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug)]
 pub struct ParentScope<'a> {
     module: Module<'a>,
     expansion: ExpnId,
     legacy: LegacyScope<'a>,
-    derives: Vec<ast::Path>,
+    derives: &'a [ast::Path],
+}
+
+impl<'a> ParentScope<'a> {
+    /// Creates a parent scope with the passed argument used as the module scope component,
+    /// and other scope components set to default empty values.
+    pub fn module(module: Module<'a>) -> ParentScope<'a> {
+        ParentScope {
+            module,
+            expansion: ExpnId::root(),
+            legacy: LegacyScope::Empty,
+            derives: &[],
+        }
+    }
 }
 
 #[derive(Eq)]
@@ -274,7 +296,7 @@
                 ItemKind::Use(..) => {
                     // don't suggest placing a use before the prelude
                     // import or other generated ones
-                    if item.span.ctxt().outer_expn_info().is_none() {
+                    if !item.span.from_expansion() {
                         self.span = Some(item.span.shrink_to_lo());
                         self.found_use = true;
                         return;
@@ -284,7 +306,7 @@
                 ItemKind::ExternCrate(_) => {}
                 // but place them before the first other item
                 _ => if self.span.map_or(true, |span| item.span < span ) {
-                    if item.span.ctxt().outer_expn_info().is_none() {
+                    if !item.span.from_expansion() {
                         // don't insert between attributes and an item
                         if item.attrs.is_empty() {
                             self.span = Some(item.span.shrink_to_lo());
@@ -409,6 +431,8 @@
     }
 }
 
+type Resolutions<'a> = RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>;
+
 /// One node in the tree of modules.
 pub struct ModuleData<'a> {
     parent: Option<Module<'a>>,
@@ -417,12 +441,11 @@
     // The def id of the closest normal module (`mod`) ancestor (including this module).
     normal_ancestor_id: DefId,
 
-    resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
-    single_segment_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>,
-                                                   Option<&'a NameBinding<'a>>)>>,
-    multi_segment_macro_resolutions: RefCell<Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
-                                                  Option<Res>)>>,
-    builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
+    // Mapping between names and their (possibly in-progress) resolutions in this module.
+    // Resolutions in modules from other crates are not populated until accessed.
+    lazy_resolutions: Resolutions<'a>,
+    // True if this is a module from other crate that needs to be populated on access.
+    populate_on_access: Cell<bool>,
 
     // Macro invocations that can expand into items in this module.
     unresolved_invocations: RefCell<FxHashSet<ExpnId>>,
@@ -435,11 +458,6 @@
     // Used to memoize the traits in this module for faster searches through all traits in scope.
     traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
 
-    // Whether this module is populated. If not populated, any attempt to
-    // access the children must be preceded with a
-    // `populate_module_if_necessary` call.
-    populated: Cell<bool>,
-
     /// Span of the module itself. Used for error reporting.
     span: Span,
 
@@ -458,33 +476,34 @@
             parent,
             kind,
             normal_ancestor_id,
-            resolutions: Default::default(),
-            single_segment_macro_resolutions: RefCell::new(Vec::new()),
-            multi_segment_macro_resolutions: RefCell::new(Vec::new()),
-            builtin_attrs: RefCell::new(Vec::new()),
+            lazy_resolutions: Default::default(),
+            populate_on_access: Cell::new(!normal_ancestor_id.is_local()),
             unresolved_invocations: Default::default(),
             no_implicit_prelude: false,
             glob_importers: RefCell::new(Vec::new()),
             globs: RefCell::new(Vec::new()),
             traits: RefCell::new(None),
-            populated: Cell::new(normal_ancestor_id.is_local()),
             span,
             expansion,
         }
     }
 
-    fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
-        for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
-            name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
+    fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
+        where R: AsMut<Resolver<'a>>, F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>)
+    {
+        for (&(ident, ns), name_resolution) in resolver.as_mut().resolutions(self).borrow().iter() {
+            name_resolution.borrow().binding.map(|binding| f(resolver, ident, ns, binding));
         }
     }
 
-    fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
-        let resolutions = self.resolutions.borrow();
+    fn for_each_child_stable<R, F>(&'a self, resolver: &mut R, mut f: F)
+        where R: AsMut<Resolver<'a>>, F: FnMut(&mut R, Ident, Namespace, &'a NameBinding<'a>)
+    {
+        let resolutions = resolver.as_mut().resolutions(self).borrow();
         let mut resolutions = resolutions.iter().collect::<Vec<_>>();
         resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
         for &(&(ident, ns), &resolution) in resolutions.iter() {
-            resolution.borrow().binding.map(|binding| f(ident, ns, binding));
+            resolution.borrow().binding.map(|binding| f(resolver, ident, ns, binding));
         }
     }
 
@@ -807,7 +826,7 @@
 
     pub definitions: Definitions,
 
-    graph_root: Module<'a>,
+    pub graph_root: Module<'a>,
 
     prelude: Option<Module<'a>>,
     pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
@@ -896,15 +915,24 @@
     local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
     unused_macros: NodeMap<Span>,
     proc_macro_stubs: NodeSet,
+    /// Traces collected during macro resolution and validated when it's complete.
+    single_segment_macro_resolutions: Vec<(Ident, MacroKind, ParentScope<'a>,
+                                           Option<&'a NameBinding<'a>>)>,
+    multi_segment_macro_resolutions: Vec<(Vec<Segment>, Span, MacroKind, ParentScope<'a>,
+                                          Option<Res>)>,
+    builtin_attrs: Vec<(Ident, ParentScope<'a>)>,
     /// Some built-in derives mark items they are applied to so they are treated specially later.
     /// Derive macros cannot modify the item themselves and have to store the markers in the global
     /// context, so they attach the markers to derive container IDs using this resolver table.
     /// FIXME: Find a way for `PartialEq` and `Eq` to emulate `#[structural_match]`
     /// by marking the produced impls rather than the original items.
     special_derives: FxHashMap<ExpnId, SpecialDerives>,
-
-    /// Maps the `ExpnId` of an expansion to its containing module or block.
-    invocations: FxHashMap<ExpnId, &'a InvocationData<'a>>,
+    /// Parent scopes in which the macros were invoked.
+    /// FIXME: `derives` are missing in these parent scopes and need to be taken from elsewhere.
+    invocation_parent_scopes: FxHashMap<ExpnId, ParentScope<'a>>,
+    /// Legacy scopes *produced* by expanding the macro invocations,
+    /// include all the `macro_rules` items and other invocations generated by them.
+    output_legacy_scopes: FxHashMap<ExpnId, LegacyScope<'a>>,
 
     /// Avoid duplicated errors for "name already defined".
     name_already_seen: FxHashMap<Name, Span>,
@@ -927,8 +955,8 @@
     name_bindings: arena::TypedArena<NameBinding<'a>>,
     import_directives: arena::TypedArena<ImportDirective<'a>>,
     name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
-    invocation_data: arena::TypedArena<InvocationData<'a>>,
     legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
+    ast_paths: arena::TypedArena<ast::Path>,
 }
 
 impl<'a> ResolverArenas<'a> {
@@ -952,13 +980,16 @@
     fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
         self.name_resolutions.alloc(Default::default())
     }
-    fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
-                             -> &'a InvocationData<'a> {
-        self.invocation_data.alloc(expansion_data)
-    }
     fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
         self.legacy_bindings.alloc(binding)
     }
+    fn alloc_ast_paths(&'a self, paths: &[ast::Path]) -> &'a [ast::Path] {
+        self.ast_paths.alloc_from_iter(paths.iter().cloned())
+    }
+}
+
+impl<'a> AsMut<Resolver<'a>> for Resolver<'a> {
+    fn as_mut(&mut self) -> &mut Resolver<'a> { self }
 }
 
 impl<'a, 'b> ty::DefIdTree for &'a Resolver<'b> {
@@ -985,11 +1016,11 @@
         } else {
             kw::Crate
         };
-        let segments = iter::once(Ident::with_empty_ctxt(root))
+        let segments = iter::once(Ident::with_dummy_span(root))
             .chain(
                 crate_root.into_iter()
                     .chain(components.iter().cloned())
-                    .map(Ident::with_empty_ctxt)
+                    .map(Ident::with_dummy_span)
             ).map(|i| self.new_ast_path_segment(i)).collect::<Vec<_>>();
 
         let path = ast::Path {
@@ -997,7 +1028,7 @@
             segments,
         };
 
-        let parent_scope = &self.dummy_parent_scope();
+        let parent_scope = &ParentScope::module(self.graph_root);
         let res = match self.resolve_ast_path(&path, ns, parent_scope) {
             Ok(res) => res,
             Err((span, error)) => {
@@ -1060,18 +1091,17 @@
                                        .collect();
 
         if !attr::contains_name(&krate.attrs, sym::no_core) {
-            extern_prelude.insert(Ident::with_empty_ctxt(sym::core), Default::default());
+            extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
             if !attr::contains_name(&krate.attrs, sym::no_std) {
-                extern_prelude.insert(Ident::with_empty_ctxt(sym::std), Default::default());
+                extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
                 if session.rust_2018() {
-                    extern_prelude.insert(Ident::with_empty_ctxt(sym::meta), Default::default());
+                    extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
                 }
             }
         }
 
-        let mut invocations = FxHashMap::default();
-        invocations.insert(ExpnId::root(),
-                           arenas.alloc_invocation_data(InvocationData::root(graph_root)));
+        let mut invocation_parent_scopes = FxHashMap::default();
+        invocation_parent_scopes.insert(ExpnId::root(), ParentScope::module(graph_root));
 
         let mut macro_defs = FxHashMap::default();
         macro_defs.insert(ExpnId::root(), root_def_id);
@@ -1143,7 +1173,8 @@
             dummy_ext_bang: Lrc::new(SyntaxExtension::dummy_bang(session.edition())),
             dummy_ext_derive: Lrc::new(SyntaxExtension::dummy_derive(session.edition())),
             non_macro_attrs: [non_macro_attr(false), non_macro_attr(true)],
-            invocations,
+            invocation_parent_scopes,
+            output_legacy_scopes: Default::default(),
             macro_defs,
             local_macro_def_scopes: FxHashMap::default(),
             name_already_seen: FxHashMap::default(),
@@ -1151,6 +1182,9 @@
             struct_constructors: Default::default(),
             unused_macros: Default::default(),
             proc_macro_stubs: Default::default(),
+            single_segment_macro_resolutions: Default::default(),
+            multi_segment_macro_resolutions: Default::default(),
+            builtin_attrs: Default::default(),
             special_derives: Default::default(),
             active_features:
                 features.declared_lib_features.iter().map(|(feat, ..)| *feat)
@@ -1182,9 +1216,8 @@
         f(self, MacroNS);
     }
 
-    fn is_builtin_macro(&mut self, def_id: Option<DefId>) -> bool {
-        def_id.and_then(|def_id| self.get_macro_by_def_id(def_id))
-              .map_or(false, |ext| ext.is_builtin)
+    fn is_builtin_macro(&mut self, res: Res) -> bool {
+        self.get_macro(res).map_or(false, |ext| ext.is_builtin)
     }
 
     fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
@@ -1203,6 +1236,7 @@
     /// Entry point to crate resolution.
     pub fn resolve_crate(&mut self, krate: &Crate) {
         ImportResolver { r: self }.finalize_imports();
+        self.finalize_macro_resolutions();
 
         self.late_resolve_crate(krate);
 
@@ -1223,6 +1257,20 @@
         self.arenas.alloc_module(module)
     }
 
+    fn resolutions(&mut self, module: Module<'a>) -> &'a Resolutions<'a> {
+        if module.populate_on_access.get() {
+            module.populate_on_access.set(false);
+            self.build_reduced_graph_external(module);
+        }
+        &module.lazy_resolutions
+    }
+
+    fn resolution(&mut self, module: Module<'a>, ident: Ident, ns: Namespace)
+                  -> &'a RefCell<NameResolution<'a>> {
+        *self.resolutions(module).borrow_mut().entry((ident.modern(), ns))
+               .or_insert_with(|| self.arenas.alloc_name_resolution())
+    }
+
     fn record_use(&mut self, ident: Ident, ns: Namespace,
                   used_binding: &'a NameBinding<'a>, is_lexical_scope: bool) {
         if let Some((b2, kind)) = used_binding.ambiguity {
@@ -1319,13 +1367,15 @@
             ScopeSet::AbsolutePath(ns) => (ns, true),
             ScopeSet::Macro(_) => (MacroNS, false),
         };
+        // Jump out of trait or enum modules, they do not act as scopes.
+        let module = parent_scope.module.nearest_item_scope();
         let mut scope = match ns {
             _ if is_absolute_path => Scope::CrateRoot,
-            TypeNS | ValueNS => Scope::Module(parent_scope.module),
+            TypeNS | ValueNS => Scope::Module(module),
             MacroNS => Scope::DeriveHelpers,
         };
         let mut ident = ident.modern();
-        let mut use_prelude = !parent_scope.module.no_implicit_prelude;
+        let mut use_prelude = !module.no_implicit_prelude;
 
         loop {
             let visit = match scope {
@@ -1355,10 +1405,11 @@
                     LegacyScope::Binding(binding) => Scope::MacroRules(
                         binding.parent_legacy_scope
                     ),
-                    LegacyScope::Invocation(invoc) => Scope::MacroRules(
-                        invoc.output_legacy_scope.get().unwrap_or(invoc.parent_legacy_scope)
+                    LegacyScope::Invocation(invoc_id) => Scope::MacroRules(
+                        self.output_legacy_scopes.get(&invoc_id).cloned()
+                            .unwrap_or(self.invocation_parent_scopes[&invoc_id].legacy)
                     ),
-                    LegacyScope::Empty => Scope::Module(parent_scope.module),
+                    LegacyScope::Empty => Scope::Module(module),
                 }
                 Scope::CrateRoot => match ns {
                     TypeNS => {
@@ -1430,7 +1481,7 @@
         }
         let (general_span, modern_span) = if ident.name == kw::SelfUpper {
             // FIXME(jseyfried) improve `Self` hygiene
-            let empty_span = ident.span.with_ctxt(SyntaxContext::empty());
+            let empty_span = ident.span.with_ctxt(SyntaxContext::root());
             (empty_span, empty_span)
         } else if ns == TypeNS {
             let modern_span = ident.span.modern();
@@ -1448,7 +1499,7 @@
             debug!("walk rib\n{:?}", ribs[i].bindings);
             // Use the rib kind to determine whether we are resolving parameters
             // (modern hygiene) or local variables (legacy hygiene).
-            let rib_ident = if let AssocItemRibKind | ItemRibKind = ribs[i].kind {
+            let rib_ident = if ribs[i].kind.contains_params() {
                 modern_ident
             } else {
                 ident
@@ -1501,7 +1552,7 @@
                 self.hygienic_lexical_parent(module, &mut ident.span)
             };
             module = unwrap_or!(opt_module, break);
-            let adjusted_parent_scope = &ParentScope { module, ..parent_scope.clone() };
+            let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
             let result = self.resolve_ident_in_module_unadjusted(
                 ModuleOrUniformRoot::Module(module),
                 ident,
@@ -1637,7 +1688,7 @@
             ModuleOrUniformRoot::Module(m) => {
                 if let Some(def) = ident.span.modernize_and_adjust(m.expansion) {
                     tmp_parent_scope =
-                        ParentScope { module: self.macro_def_scope(def), ..parent_scope.clone() };
+                        ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
                     adjusted_parent_scope = &tmp_parent_scope;
                 }
             }
@@ -2606,7 +2657,6 @@
                     return None;
                 };
                 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
-                self.populate_module_if_necessary(&crate_root);
                 Some((crate_root, ty::Visibility::Public, DUMMY_SP, ExpnId::root())
                     .to_name_binding(self.arenas))
             }
@@ -2624,7 +2674,7 @@
         let path = if path_str.starts_with("::") {
             ast::Path {
                 span,
-                segments: iter::once(Ident::with_empty_ctxt(kw::PathRoot))
+                segments: iter::once(Ident::with_dummy_span(kw::PathRoot))
                     .chain({
                         path_str.split("::").skip(1).map(Ident::from_str)
                     })
@@ -2645,7 +2695,7 @@
             let def_id = self.definitions.local_def_id(module_id);
             self.module_map.get(&def_id).copied().unwrap_or(self.graph_root)
         });
-        let parent_scope = &ParentScope { module, ..self.dummy_parent_scope() };
+        let parent_scope = &ParentScope::module(module);
         let res = self.resolve_ast_path(&path, ns, parent_scope).map_err(|_| ())?;
         Ok((path, res))
     }
@@ -2713,7 +2763,7 @@
     fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
         if let ModuleKind::Def(.., name) = module.kind {
             if let Some(parent) = module.parent {
-                names.push(Ident::with_empty_ctxt(name));
+                names.push(Ident::with_dummy_span(name));
                 collect_mod(names, parent);
             }
         } else {
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 71e26da..6f49377 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -1,12 +1,13 @@
+//! A bunch of methods and structures more or less related to resolving macros and
+//! interface provided by `Resolver` to macro expander.
+
 use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc, Determinacy};
 use crate::{CrateLint, Resolver, ResolutionError, Scope, ScopeSet, ParentScope, Weak};
-use crate::{Module, ModuleKind, NameBinding, PathResult, Segment, ToNameBinding};
+use crate::{ModuleKind, NameBinding, PathResult, Segment, ToNameBinding};
 use crate::{ModuleOrUniformRoot, KNOWN_TOOLS};
 use crate::Namespace::*;
-use crate::build_reduced_graph::BuildReducedGraphVisitor;
 use crate::resolve_imports::ImportResolver;
 use rustc::hir::def::{self, DefKind, NonMacroAttrKind};
-use rustc::hir::map::DefCollector;
 use rustc::middle::stability;
 use rustc::{ty, lint, span_bug};
 use syntax::ast::{self, Ident};
@@ -15,43 +16,18 @@
 use syntax::ext::base::{self, Indeterminate, SpecialDerives};
 use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::expand::{AstFragment, Invocation, InvocationKind};
-use syntax::ext::hygiene::{self, ExpnId, ExpnInfo, ExpnKind};
+use syntax::ext::hygiene::{self, ExpnId, ExpnData, ExpnKind};
 use syntax::ext::tt::macro_rules;
 use syntax::feature_gate::{emit_feature_err, is_builtin_attr_name};
 use syntax::feature_gate::GateIssue;
 use syntax::symbol::{Symbol, kw, sym};
 use syntax_pos::{Span, DUMMY_SP};
 
-use std::cell::Cell;
 use std::{mem, ptr};
 use rustc_data_structures::sync::Lrc;
 
 type Res = def::Res<ast::NodeId>;
 
-// FIXME: Merge this with `ParentScope`.
-#[derive(Clone, Debug)]
-pub struct InvocationData<'a> {
-    /// The module in which the macro was invoked.
-    crate module: Module<'a>,
-    /// The legacy scope in which the macro was invoked.
-    /// The invocation path is resolved in this scope.
-    crate parent_legacy_scope: LegacyScope<'a>,
-    /// The legacy scope *produced* by expanding this macro invocation,
-    /// includes all the macro_rules items, other invocations, etc generated by it.
-    /// `None` if the macro is not expanded yet.
-    crate output_legacy_scope: Cell<Option<LegacyScope<'a>>>,
-}
-
-impl<'a> InvocationData<'a> {
-    pub fn root(graph_root: Module<'a>) -> Self {
-        InvocationData {
-            module: graph_root,
-            parent_legacy_scope: LegacyScope::Empty,
-            output_legacy_scope: Cell::new(None),
-        }
-    }
-}
-
 /// Binding produced by a `macro_rules` item.
 /// Not modularized, can shadow previous legacy bindings, etc.
 #[derive(Debug)]
@@ -75,7 +51,7 @@
     Binding(&'a LegacyBinding<'a>),
     /// The scope introduced by a macro invocation that can potentially
     /// create a `macro_rules!` macro definition.
-    Invocation(&'a InvocationData<'a>),
+    Invocation(ExpnId),
 }
 
 // Macro namespace is separated into two sub-namespaces, one for bang macros and
@@ -120,17 +96,12 @@
     }
 
     fn get_module_scope(&mut self, id: ast::NodeId) -> ExpnId {
-        let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::default(
+        let expn_id = ExpnId::fresh(Some(ExpnData::default(
             ExpnKind::Macro(MacroKind::Attr, sym::test_case), DUMMY_SP, self.session.edition()
-        ));
-        let expn_id = span.ctxt().outer_expn();
+        )));
         let module = self.module_map[&self.definitions.local_def_id(id)];
+        self.invocation_parent_scopes.insert(expn_id, ParentScope::module(module));
         self.definitions.set_invocation_parent(expn_id, module.def_id().unwrap().index);
-        self.invocations.insert(expn_id, self.arenas.alloc_invocation_data(InvocationData {
-            module,
-            parent_legacy_scope: LegacyScope::Empty,
-            output_legacy_scope: Cell::new(None),
-        }));
         expn_id
     }
 
@@ -144,29 +115,23 @@
         });
     }
 
-    fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment,
-                                            derives: &[ExpnId]) {
-        fragment.visit_with(&mut DefCollector::new(&mut self.definitions, expn_id));
-
-        let invocation = self.invocations[&expn_id];
-        invocation.module.unresolved_invocations.borrow_mut().remove(&expn_id);
-        invocation.module.unresolved_invocations.borrow_mut().extend(derives);
-        let parent_def = self.definitions.invocation_parent(expn_id);
+    fn visit_ast_fragment_with_placeholders(
+        &mut self, expansion: ExpnId, fragment: &AstFragment, derives: &[ExpnId]
+    ) {
+        // Fill in some data for derives if the fragment is from a derive container.
+        // We are inside the `expansion` now, but other parent scope components are still the same.
+        let parent_scope = ParentScope { expansion, ..self.invocation_parent_scopes[&expansion] };
+        let parent_def = self.definitions.invocation_parent(expansion);
+        self.invocation_parent_scopes.extend(derives.iter().map(|&derive| (derive, parent_scope)));
         for &derive_invoc_id in derives {
             self.definitions.set_invocation_parent(derive_invoc_id, parent_def);
         }
-        self.invocations.extend(derives.iter().map(|&derive| (derive, invocation)));
-        let mut visitor = BuildReducedGraphVisitor {
-            r: self,
-            parent_scope: ParentScope {
-                module: invocation.module,
-                expansion: expn_id,
-                legacy: invocation.parent_legacy_scope,
-                derives: Vec::new(),
-            },
-        };
-        fragment.visit_with(&mut visitor);
-        invocation.output_legacy_scope.set(Some(visitor.parent_scope.legacy));
+        parent_scope.module.unresolved_invocations.borrow_mut().remove(&expansion);
+        parent_scope.module.unresolved_invocations.borrow_mut().extend(derives);
+
+        // Integrate the new AST fragment into all the definition and module structures.
+        let output_legacy_scope = self.build_reduced_graph(fragment, parent_scope);
+        self.output_legacy_scopes.insert(expansion, output_legacy_scope);
     }
 
     fn register_builtin_macro(&mut self, ident: ast::Ident, ext: SyntaxExtension) {
@@ -182,13 +147,14 @@
 
     fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: ExpnId, force: bool)
                                 -> Result<Option<Lrc<SyntaxExtension>>, Indeterminate> {
-        let (path, kind, derives_in_scope, after_derive) = match invoc.kind {
+        let parent_scope = self.invocation_parent_scopes[&invoc_id];
+        let (path, kind, derives, after_derive) = match invoc.kind {
             InvocationKind::Attr { ref attr, ref derives, after_derive, .. } =>
-                (&attr.path, MacroKind::Attr, derives.clone(), after_derive),
+                (&attr.path, MacroKind::Attr, self.arenas.alloc_ast_paths(derives), after_derive),
             InvocationKind::Bang { ref mac, .. } =>
-                (&mac.path, MacroKind::Bang, Vec::new(), false),
+                (&mac.path, MacroKind::Bang, &[][..], false),
             InvocationKind::Derive { ref path, .. } =>
-                (path, MacroKind::Derive, Vec::new(), false),
+                (path, MacroKind::Derive, &[][..], false),
             InvocationKind::DeriveContainer { ref derives, .. } => {
                 // Block expansion of derives in the container until we know whether one of them
                 // is a built-in `Copy`. Skip the resolution if there's only one derive - either
@@ -196,10 +162,9 @@
                 // will automatically knows about itself.
                 let mut result = Ok(None);
                 if derives.len() > 1 {
-                    let parent_scope = &self.invoc_parent_scope(invoc_id, Vec::new());
                     for path in derives {
                         match self.resolve_macro_path(path, Some(MacroKind::Derive),
-                                                      parent_scope, true, force) {
+                                                      &parent_scope, true, force) {
                             Ok((Some(ref ext), _)) if ext.is_derive_copy => {
                                 self.add_derives(invoc.expansion_data.id, SpecialDerives::COPY);
                                 return Ok(None);
@@ -213,11 +178,14 @@
             }
         };
 
-        let parent_scope = &self.invoc_parent_scope(invoc_id, derives_in_scope);
+        // Derives are not included when `invocations` are collected, so we have to add them here.
+        let parent_scope = &ParentScope { derives, ..parent_scope };
         let (ext, res) = self.smart_resolve_macro_path(path, kind, parent_scope, force)?;
 
         let span = invoc.span();
-        invoc.expansion_data.id.set_expn_info(ext.expn_info(span, fast_print_path(path)));
+        invoc.expansion_data.id.set_expn_data(
+            ext.expn_data(parent_scope.expansion, span, fast_print_path(path))
+        );
 
         if let Res::Def(_, def_id) = res {
             if after_derive {
@@ -251,20 +219,6 @@
 }
 
 impl<'a> Resolver<'a> {
-    pub fn dummy_parent_scope(&self) -> ParentScope<'a> {
-        self.invoc_parent_scope(ExpnId::root(), Vec::new())
-    }
-
-    fn invoc_parent_scope(&self, invoc_id: ExpnId, derives: Vec<ast::Path>) -> ParentScope<'a> {
-        let invoc = self.invocations[&invoc_id];
-        ParentScope {
-            module: invoc.module.nearest_item_scope(),
-            expansion: invoc_id.parent(),
-            legacy: invoc.parent_legacy_scope,
-            derives,
-        }
-    }
-
     /// Resolve macro path with error reporting and recovery.
     fn smart_resolve_macro_path(
         &mut self,
@@ -346,8 +300,7 @@
 
         // Possibly apply the macro helper hack
         if kind == Some(MacroKind::Bang) && path.len() == 1 &&
-           path[0].ident.span.ctxt().outer_expn_info()
-               .map_or(false, |info| info.local_inner_macros) {
+           path[0].ident.span.ctxt().outer_expn_data().local_inner_macros {
             let root = Ident::new(kw::DollarCrate, path[0].ident.span);
             path.insert(0, Segment::from_ident(root));
         }
@@ -367,8 +320,8 @@
 
             if trace {
                 let kind = kind.expect("macro kind must be specified if tracing is enabled");
-                parent_scope.module.multi_segment_macro_resolutions.borrow_mut()
-                    .push((path, path_span, kind, parent_scope.clone(), res.ok()));
+                self.multi_segment_macro_resolutions
+                    .push((path, path_span, kind, *parent_scope, res.ok()));
             }
 
             self.prohibit_imported_non_macro_attrs(None, res.ok(), path_span);
@@ -384,8 +337,8 @@
 
             if trace {
                 let kind = kind.expect("macro kind must be specified if tracing is enabled");
-                parent_scope.module.single_segment_macro_resolutions.borrow_mut()
-                    .push((path[0].ident, kind, parent_scope.clone(), binding.ok()));
+                self.single_segment_macro_resolutions
+                    .push((path[0].ident, kind, *parent_scope, binding.ok()));
             }
 
             let res = binding.map(|binding| binding.res());
@@ -454,8 +407,8 @@
             let result = match scope {
                 Scope::DeriveHelpers => {
                     let mut result = Err(Determinacy::Determined);
-                    for derive in &parent_scope.derives {
-                        let parent_scope = &ParentScope { derives: Vec::new(), ..*parent_scope };
+                    for derive in parent_scope.derives {
+                        let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
                         match this.resolve_macro_path(derive, Some(MacroKind::Derive),
                                                       parent_scope, true, force) {
                             Ok((Some(ext), _)) => if ext.helper_attrs.contains(&ident.name) {
@@ -475,8 +428,9 @@
                 Scope::MacroRules(legacy_scope) => match legacy_scope {
                     LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident =>
                         Ok((legacy_binding.binding, Flags::MACRO_RULES)),
-                    LegacyScope::Invocation(invoc) if invoc.output_legacy_scope.get().is_none() =>
-                        Err(Determinacy::Undetermined),
+                    LegacyScope::Invocation(invoc_id)
+                        if !this.output_legacy_scopes.contains_key(&invoc_id) =>
+                            Err(Determinacy::Undetermined),
                     _ => Err(Determinacy::Determined),
                 }
                 Scope::CrateRoot => {
@@ -500,7 +454,7 @@
                     }
                 }
                 Scope::Module(module) => {
-                    let adjusted_parent_scope = &ParentScope { module, ..parent_scope.clone() };
+                    let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
                     let binding = this.resolve_ident_in_module_unadjusted_ext(
                         ModuleOrUniformRoot::Module(module),
                         ident,
@@ -575,7 +529,7 @@
                             false,
                             path_span,
                         ) {
-                            if use_prelude || this.is_builtin_macro(binding.res().opt_def_id()) {
+                            if use_prelude || this.is_builtin_macro(binding.res()) {
                                 result = Ok((binding, Flags::PRELUDE | Flags::MISC_FROM_PRELUDE));
                             }
                         }
@@ -694,7 +648,7 @@
         }
     }
 
-    pub fn finalize_current_module_macro_resolutions(&mut self, module: Module<'a>) {
+    crate fn finalize_macro_resolutions(&mut self) {
         let check_consistency = |this: &mut Self, path: &[Segment], span, kind: MacroKind,
                                  initial_res: Option<Res>, res: Res| {
             if let Some(initial_res) = initial_res {
@@ -730,8 +684,7 @@
             }
         };
 
-        let macro_resolutions =
-            mem::take(&mut *module.multi_segment_macro_resolutions.borrow_mut());
+        let macro_resolutions = mem::take(&mut self.multi_segment_macro_resolutions);
         for (mut path, path_span, kind, parent_scope, initial_res) in macro_resolutions {
             // FIXME: Path resolution will ICE if segment IDs present.
             for seg in &mut path { seg.id = None; }
@@ -758,8 +711,7 @@
             }
         }
 
-        let macro_resolutions =
-            mem::take(&mut *module.single_segment_macro_resolutions.borrow_mut());
+        let macro_resolutions = mem::take(&mut self.single_segment_macro_resolutions);
         for (ident, kind, parent_scope, initial_binding) in macro_resolutions {
             match self.early_resolve_ident_in_lexical_scope(ident, ScopeSet::Macro(kind),
                                                             &parent_scope, true, true, ident.span) {
@@ -784,7 +736,7 @@
             }
         }
 
-        let builtin_attrs = mem::take(&mut *module.builtin_attrs.borrow_mut());
+        let builtin_attrs = mem::take(&mut self.builtin_attrs);
         for (ident, parent_scope) in builtin_attrs {
             let _ = self.early_resolve_ident_in_lexical_scope(
                 ident, ScopeSet::Macro(MacroKind::Attr), &parent_scope, true, true, ident.span
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index 00e89f0fda..b49f186 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -1,3 +1,5 @@
+//! A bunch of methods and structures more or less related to resolving imports.
+
 use ImportDirectiveSubclass::*;
 
 use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
@@ -5,9 +7,8 @@
 use crate::Determinacy::{self, *};
 use crate::Namespace::{self, TypeNS, MacroNS};
 use crate::{NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError};
-use crate::{Resolver, ResolutionError, Segment};
+use crate::{Resolver, ResolutionError, Segment, ModuleKind};
 use crate::{names_to_string, module_to_string};
-use crate::ModuleKind;
 use crate::diagnostics::Suggestion;
 
 use errors::Applicability;
@@ -35,7 +36,7 @@
 
 use log::*;
 
-use std::cell::{Cell, RefCell};
+use std::cell::Cell;
 use std::{mem, ptr};
 
 type Res = def::Res<NodeId>;
@@ -159,12 +160,6 @@
 }
 
 impl<'a> Resolver<'a> {
-    crate fn resolution(&self, module: Module<'a>, ident: Ident, ns: Namespace)
-                  -> &'a RefCell<NameResolution<'a>> {
-        *module.resolutions.borrow_mut().entry((ident.modern(), ns))
-               .or_insert_with(|| self.arenas.alloc_name_resolution())
-    }
-
     crate fn resolve_ident_in_module_unadjusted(
         &mut self,
         module: ModuleOrUniformRoot<'a>,
@@ -240,8 +235,6 @@
             }
         };
 
-        self.populate_module_if_necessary(module);
-
         let resolution = self.resolution(module, ident, ns)
             .try_borrow_mut()
             .map_err(|_| (Determined, Weak::No))?; // This happens when there is a cycle of imports.
@@ -394,7 +387,7 @@
             match ident.span.glob_adjust(module.expansion, glob_import.span) {
                 Some(Some(def)) => {
                     tmp_parent_scope =
-                        ParentScope { module: self.macro_def_scope(def), ..parent_scope.clone() };
+                        ParentScope { module: self.macro_def_scope(def), ..*parent_scope };
                     adjusted_parent_scope = &tmp_parent_scope;
                 }
                 Some(None) => {}
@@ -848,7 +841,7 @@
         directive.vis.set(orig_vis);
         let module = match path_res {
             PathResult::Module(module) => {
-                // Consistency checks, analogous to `finalize_current_module_macro_resolutions`.
+                // Consistency checks, analogous to `finalize_macro_resolutions`.
                 if let Some(initial_module) = directive.imported_module.get() {
                     if !ModuleOrUniformRoot::same_def(module, initial_module) && no_ambiguity {
                         span_bug!(directive.span, "inconsistent resolution for an import");
@@ -973,7 +966,7 @@
 
             match binding {
                 Ok(binding) => {
-                    // Consistency checks, analogous to `finalize_current_module_macro_resolutions`.
+                    // Consistency checks, analogous to `finalize_macro_resolutions`.
                     let initial_res = source_bindings[ns].get().map(|initial_binding| {
                         all_ns_err = false;
                         if let Some(target_binding) = target_bindings[ns].get() {
@@ -1025,7 +1018,8 @@
 
             return if all_ns_failed {
                 let resolutions = match module {
-                    ModuleOrUniformRoot::Module(module) => Some(module.resolutions.borrow()),
+                    ModuleOrUniformRoot::Module(module) =>
+                        Some(self.r.resolutions(module).borrow()),
                     _ => None,
                 };
                 let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
@@ -1263,8 +1257,6 @@
             }
         };
 
-        self.r.populate_module_if_necessary(module);
-
         if module.is_trait() {
             self.r.session.span_err(directive.span, "items in traits are not importable.");
             return;
@@ -1280,8 +1272,8 @@
 
         // Ensure that `resolutions` isn't borrowed during `try_define`,
         // since it might get updated via a glob cycle.
-        let bindings = module.resolutions.borrow().iter().filter_map(|(&ident, resolution)| {
-            resolution.borrow().binding().map(|binding| (ident, binding))
+        let bindings = self.r.resolutions(module).borrow().iter().filter_map(|(ident, resolution)| {
+            resolution.borrow().binding().map(|binding| (*ident, binding))
         }).collect::<Vec<_>>();
         for ((mut ident, ns), binding) in bindings {
             let scope = match ident.span.reverse_glob_adjust(module.expansion, directive.span) {
@@ -1308,7 +1300,7 @@
 
         let mut reexports = Vec::new();
 
-        for (&(ident, ns), resolution) in module.resolutions.borrow().iter() {
+        for (&(ident, ns), resolution) in self.r.resolutions(module).borrow().iter() {
             let resolution = &mut *resolution.borrow_mut();
             let binding = match resolution.binding {
                 Some(binding) => binding,
@@ -1367,8 +1359,8 @@
                             Some(ModuleOrUniformRoot::Module(module)) => module,
                             _ => bug!("module should exist"),
                         };
-                        let resolutions = imported_module.parent.expect("parent should exist")
-                            .resolutions.borrow();
+                        let parent_module = imported_module.parent.expect("parent should exist");
+                        let resolutions = self.r.resolutions(parent_module).borrow();
                         let enum_path_segment_index = directive.module_path.len() - 1;
                         let enum_ident = directive.module_path[enum_path_segment_index].ident;
 
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 9da6cd8..0bbbbb8 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -1156,7 +1156,7 @@
 // Helper function to determine if a span came from a
 // macro expansion or syntax extension.
 fn generated_code(span: Span) -> bool {
-    span.ctxt() != NO_EXPANSION || span.is_dummy()
+    span.from_expansion() || span.is_dummy()
 }
 
 // DefId::index is a newtype and so the JSON serialisation is ugly. Therefore
diff --git a/src/librustc_target/spec/aarch64_wrs_vxworks.rs b/src/librustc_target/spec/aarch64_wrs_vxworks.rs
index 6ad6632..65caeac 100644
--- a/src/librustc_target/spec/aarch64_wrs_vxworks.rs
+++ b/src/librustc_target/spec/aarch64_wrs_vxworks.rs
@@ -9,15 +9,14 @@
         target_endian: "little".to_string(),
         target_pointer_width: "64".to_string(),
         target_c_int_width: "32".to_string(),
-        target_env: "gnu".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),
         target_os: "vxworks".to_string(),
-        target_vendor: "unknown".to_string(),
+        target_env: "gnu".to_string(),
+        target_vendor: "wrs".to_string(),
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             abi_blacklist: super::arm_base::abi_blacklist(),
-            target_mcount: "\u{1}_mcount".to_string(),
             .. base
         },
     })
diff --git a/src/librustc_target/spec/arm_wrs_vxworks_sf.rs b/src/librustc_target/spec/arm_wrs_vxworks_sf.rs
deleted file mode 100644
index bde903d..0000000
--- a/src/librustc_target/spec/arm_wrs_vxworks_sf.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
-
-pub fn target() -> TargetResult {
-    let mut base = super::vxworks_base::opts();
-    base.max_atomic_width = Some(64);
-    Ok(Target {
-        llvm_target: "arm-unknown-linux-gnueabi".to_string(),
-        target_endian: "little".to_string(),
-        target_pointer_width: "32".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
-        arch: "arm".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-
-        options: TargetOptions {
-            features: "+strict-align,+v6".to_string(),
-            abi_blacklist: super::arm_base::abi_blacklist(),
-            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
-            .. base
-        },
-    })
-}
diff --git a/src/librustc_target/spec/armv7_wrs_vxworks.rs b/src/librustc_target/spec/armv7_wrs_vxworks.rs
deleted file mode 100644
index 06c51ae..0000000
--- a/src/librustc_target/spec/armv7_wrs_vxworks.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
-
-// This target is for glibc Linux on ARMv7 without NEON or
-// thumb-mode. See the thumbv7neon variant for enabling both.
-
-pub fn target() -> TargetResult {
-    let base = super::vxworks_base::opts();
-    Ok(Target {
-        llvm_target: "armv7-unknown-linux-gnueabihf".to_string(),
-        target_endian: "little".to_string(),
-        target_pointer_width: "32".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
-        arch: "arm".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-
-        options: TargetOptions {
-            // Info about features at https://wiki.debian.org/ArmHardFloatPort
-            features: "+v7,+vfp3,-d32,+thumb2,-neon".to_string(),
-            cpu: "generic".to_string(),
-            max_atomic_width: Some(64),
-            abi_blacklist: super::arm_base::abi_blacklist(),
-            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
-            position_independent_executables: false,
-            .. base
-        }
-    })
-}
diff --git a/src/librustc_target/spec/arm_wrs_vxworks.rs b/src/librustc_target/spec/armv7_wrs_vxworks_eabihf.rs
similarity index 77%
rename from src/librustc_target/spec/arm_wrs_vxworks.rs
rename to src/librustc_target/spec/armv7_wrs_vxworks_eabihf.rs
index 06c51ae..9e3b24d 100644
--- a/src/librustc_target/spec/arm_wrs_vxworks.rs
+++ b/src/librustc_target/spec/armv7_wrs_vxworks_eabihf.rs
@@ -1,8 +1,5 @@
 use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
-// This target is for glibc Linux on ARMv7 without NEON or
-// thumb-mode. See the thumbv7neon variant for enabling both.
-
 pub fn target() -> TargetResult {
     let base = super::vxworks_base::opts();
     Ok(Target {
@@ -14,17 +11,14 @@
         arch: "arm".to_string(),
         target_os: "vxworks".to_string(),
         target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
+        target_vendor: "wrs".to_string(),
         linker_flavor: LinkerFlavor::Gcc,
-
         options: TargetOptions {
             // Info about features at https://wiki.debian.org/ArmHardFloatPort
             features: "+v7,+vfp3,-d32,+thumb2,-neon".to_string(),
             cpu: "generic".to_string(),
             max_atomic_width: Some(64),
             abi_blacklist: super::arm_base::abi_blacklist(),
-            target_mcount: "\u{1}__gnu_mcount_nc".to_string(),
-            position_independent_executables: false,
             .. base
         }
     })
diff --git a/src/librustc_target/spec/i586_wrs_vxworks.rs b/src/librustc_target/spec/i586_wrs_vxworks.rs
deleted file mode 100644
index 355250e..0000000
--- a/src/librustc_target/spec/i586_wrs_vxworks.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-use crate::spec::TargetResult;
-
-pub fn target() -> TargetResult {
-    let mut base = super::i686_wrs_vxworks::target()?;
-    base.options.cpu = "pentium".to_string();
-    base.llvm_target = "i586-unknown-linux-gnu".to_string();
-    Ok(base)
-}
diff --git a/src/librustc_target/spec/i686_wrs_vxworks.rs b/src/librustc_target/spec/i686_wrs_vxworks.rs
index 4b1ff5c..c5f9583 100644
--- a/src/librustc_target/spec/i686_wrs_vxworks.rs
+++ b/src/librustc_target/spec/i686_wrs_vxworks.rs
@@ -16,7 +16,7 @@
         arch: "x86".to_string(),
         target_os: "vxworks".to_string(),
         target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
+        target_vendor: "wrs".to_string(),
         linker_flavor: LinkerFlavor::Gcc,
         options: base,
     })
diff --git a/src/librustc_target/spec/i686_wrs_vxworks_gnu.rs b/src/librustc_target/spec/i686_wrs_vxworks_gnu.rs
deleted file mode 100644
index 4b1ff5c..0000000
--- a/src/librustc_target/spec/i686_wrs_vxworks_gnu.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetResult};
-
-pub fn target() -> TargetResult {
-    let mut base = super::vxworks_base::opts();
-    base.cpu = "pentium4".to_string();
-    base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
-    base.stack_probes = true;
-
-    Ok(Target {
-        llvm_target: "i686-unknown-linux-gnu".to_string(),
-        target_endian: "little".to_string(),
-        target_pointer_width: "32".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128".to_string(),
-        arch: "x86".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-        options: base,
-    })
-}
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 9a009ca..539e28f 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -398,6 +398,7 @@
 
     ("aarch64-unknown-openbsd", aarch64_unknown_openbsd),
     ("i686-unknown-openbsd", i686_unknown_openbsd),
+    ("sparc64-unknown-openbsd", sparc64_unknown_openbsd),
     ("x86_64-unknown-openbsd", x86_64_unknown_openbsd),
 
     ("aarch64-unknown-netbsd", aarch64_unknown_netbsd),
@@ -492,10 +493,9 @@
 
     ("nvptx64-nvidia-cuda", nvptx64_nvidia_cuda),
 
-    ("x86_64-wrs-vxworks", x86_64_wrs_vxworks),
     ("i686-wrs-vxworks", i686_wrs_vxworks),
-    ("i586-wrs-vxworks", i586_wrs_vxworks),
-    ("armv7-wrs-vxworks", armv7_wrs_vxworks),
+    ("x86_64-wrs-vxworks", x86_64_wrs_vxworks),
+    ("armv7-wrs-vxworks-eabihf", armv7_wrs_vxworks_eabihf),
     ("aarch64-wrs-vxworks", aarch64_wrs_vxworks),
     ("powerpc-wrs-vxworks", powerpc_wrs_vxworks),
     ("powerpc-wrs-vxworks-spe", powerpc_wrs_vxworks_spe),
diff --git a/src/librustc_target/spec/powerpc64_wrs_vxworks.rs b/src/librustc_target/spec/powerpc64_wrs_vxworks.rs
index a952070..27a84b9 100644
--- a/src/librustc_target/spec/powerpc64_wrs_vxworks.rs
+++ b/src/librustc_target/spec/powerpc64_wrs_vxworks.rs
@@ -15,10 +15,9 @@
         arch: "powerpc64".to_string(),
         target_os: "vxworks".to_string(),
         target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
+        target_vendor: "wrs".to_string(),
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
-            target_mcount: "_mcount".to_string(),
             .. base
         },
     })
diff --git a/src/librustc_target/spec/powerpc64_wrs_vxworks_gnusf.rs b/src/librustc_target/spec/powerpc64_wrs_vxworks_gnusf.rs
deleted file mode 100644
index c2dae85..0000000
--- a/src/librustc_target/spec/powerpc64_wrs_vxworks_gnusf.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
-
-pub fn target() -> TargetResult {
-    let mut base = super::vxworks_base::opts();
-    base.cpu = "ppc64".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
-    base.max_atomic_width = Some(64);
-
-    Ok(Target {
-        llvm_target: "powerpc64-unknown-linux-gnu".to_string(),
-        target_endian: "big".to_string(),
-        target_pointer_width: "64".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "E-m:e-i64:64-n32:64".to_string(),
-        arch: "powerpc64".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "unknown".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-        options: TargetOptions {
-            features: "-hard-float".to_string(),
-            target_mcount: "_mcount".to_string(),
-            .. base
-        },
-    })
-}
diff --git a/src/librustc_target/spec/powerpc_wrs_vxworks.rs b/src/librustc_target/spec/powerpc_wrs_vxworks.rs
index 2e833ee..a4d2897 100644
--- a/src/librustc_target/spec/powerpc_wrs_vxworks.rs
+++ b/src/librustc_target/spec/powerpc_wrs_vxworks.rs
@@ -19,7 +19,6 @@
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             features: "+secure-plt".to_string(),
-            target_mcount: "_mcount".to_string(),
             .. base
         },
     })
diff --git a/src/librustc_target/spec/powerpc_wrs_vxworks_gnusf.rs b/src/librustc_target/spec/powerpc_wrs_vxworks_gnusf.rs
deleted file mode 100644
index 43723ea..0000000
--- a/src/librustc_target/spec/powerpc_wrs_vxworks_gnusf.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
-
-pub fn target() -> TargetResult {
-    let mut base = super::vxworks_base::opts();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("--secure-plt".to_string());
-    base.max_atomic_width = Some(32);
-
-    Ok(Target {
-        llvm_target: "powerpc-unknown-linux-gnu".to_string(),
-        target_endian: "big".to_string(),
-        target_pointer_width: "32".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "E-m:e-p:32:32-i64:64-n32".to_string(),
-        arch: "powerpc".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "wrs".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-        options: TargetOptions {
-            features: "+secure-plt,-hard-float".to_string(),
-            target_mcount: "_mcount".to_string(),
-            .. base
-        },
-    })
-}
diff --git a/src/librustc_target/spec/powerpc_wrs_vxworks_gnuspesf.rs b/src/librustc_target/spec/powerpc_wrs_vxworks_gnuspesf.rs
deleted file mode 100644
index 8f23623..0000000
--- a/src/librustc_target/spec/powerpc_wrs_vxworks_gnuspesf.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
-
-pub fn target() -> TargetResult {
-    let mut base = super::vxworks_base::opts();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-mspe".to_string());
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("--secure-plt".to_string());
-    base.max_atomic_width = Some(32);
-
-    Ok(Target {
-        llvm_target: "powerpc-unknown-linux-gnuspe".to_string(),
-        target_endian: "big".to_string(),
-        target_pointer_width: "32".to_string(),
-        target_c_int_width: "32".to_string(),
-        data_layout: "E-m:e-p:32:32-i64:64-n32".to_string(),
-        arch: "powerpc".to_string(),
-        target_os: "vxworks".to_string(),
-        target_env: "gnu".to_string(),
-        target_vendor: "wrs".to_string(),
-        linker_flavor: LinkerFlavor::Gcc,
-        options: TargetOptions {
-            // feature msync would disable instruction 'fsync' which is not supported by fsl_p1p2
-            features: "+secure-plt,+msync,-hard-float".to_string(),
-            target_mcount: "_mcount".to_string(),
-            .. base
-        },
-    })
-}
diff --git a/src/librustc_target/spec/powerpc_wrs_vxworks_spe.rs b/src/librustc_target/spec/powerpc_wrs_vxworks_spe.rs
index 2305b4b..90118a14 100644
--- a/src/librustc_target/spec/powerpc_wrs_vxworks_spe.rs
+++ b/src/librustc_target/spec/powerpc_wrs_vxworks_spe.rs
@@ -20,7 +20,6 @@
         options: TargetOptions {
             // feature msync would disable instruction 'fsync' which is not supported by fsl_p1p2
             features: "+secure-plt,+msync".to_string(),
-            target_mcount: "_mcount".to_string(),
             .. base
         },
     })
diff --git a/src/librustc_target/spec/sparc64_unknown_openbsd.rs b/src/librustc_target/spec/sparc64_unknown_openbsd.rs
new file mode 100644
index 0000000..229e062
--- /dev/null
+++ b/src/librustc_target/spec/sparc64_unknown_openbsd.rs
@@ -0,0 +1,22 @@
+use crate::spec::{LinkerFlavor, Target, TargetResult};
+
+pub fn target() -> TargetResult {
+    let mut base = super::openbsd_base::opts();
+    base.cpu = "v9".to_string();
+    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.max_atomic_width = Some(64);
+
+    Ok(Target {
+        llvm_target: "sparc64-unknown-openbsd".to_string(),
+        target_endian: "big".to_string(),
+        target_pointer_width: "64".to_string(),
+        target_c_int_width: "32".to_string(),
+        data_layout: "E-m:e-i64:64-n32:64-S128".to_string(),
+        arch: "sparc64".to_string(),
+        target_os: "openbsd".to_string(),
+        target_env: String::new(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+        options: base,
+    })
+}
diff --git a/src/librustc_target/spec/vxworks_base.rs b/src/librustc_target/spec/vxworks_base.rs
index 6db56c5..16acd41 100644
--- a/src/librustc_target/spec/vxworks_base.rs
+++ b/src/librustc_target/spec/vxworks_base.rs
@@ -1,7 +1,11 @@
-use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
+    let mut args_crt = LinkArgs::new();
+    args_crt.insert(LinkerFlavor::Gcc, vec![
+        "--static-crt".to_string(),
+    ]);
     let mut args = LinkArgs::new();
     args.insert(LinkerFlavor::Gcc, vec![
         // We want to be able to strip as much executable code as possible
@@ -12,30 +16,25 @@
         // following libraries so we're sure to pass it as one of the first
         // arguments.
         "-Wl,--as-needed".to_string(),
-
-        // Always enable NX protection when it is available
-        "-Wl,-z,noexecstack".to_string(),
-    ]);
-
-    let mut late_lk_args = LinkArgs::new();
-    late_lk_args.insert(LinkerFlavor::Gcc, vec![
-        "-lnet".to_string(),
-        "-lunix".to_string(),
     ]);
 
     TargetOptions {
-        linker: Some("vx-cxx".to_string()),
+        linker: Some("wr-c++".to_string()),
         exe_suffix: ".vxe".to_string(),
-        late_link_args: late_lk_args,
         dynamic_linking: true,
         executables: true,
         target_family: Some("unix".to_string()),
         linker_is_gnu: true,
         has_rpath: true,
         pre_link_args: args,
-        position_independent_executables: true,
-        relro_level: RelroLevel::Full,
+        position_independent_executables: false,
         has_elf_tls: true,
+        pre_link_args_crt: args_crt,
+        crt_static_default: true,
+        crt_static_respected: true,
+        crt_static_allows_dylibs: true,
+        // VxWorks needs to implement this to support profiling
+        target_mcount: "_mcount".to_string(),
         .. Default::default()
     }
 }
diff --git a/src/librustc_target/spec/x86_64_wrs_vxworks.rs b/src/librustc_target/spec/x86_64_wrs_vxworks.rs
index eac7cd7..1ab2f3a 100644
--- a/src/librustc_target/spec/x86_64_wrs_vxworks.rs
+++ b/src/librustc_target/spec/x86_64_wrs_vxworks.rs
@@ -6,6 +6,7 @@
     base.max_atomic_width = Some(64);
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
     base.stack_probes = true;
+    base.disable_redzone = true;
 
     Ok(Target {
         llvm_target: "x86_64-unknown-linux-gnu".to_string(),
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index ed25601..de5ba8b 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -347,9 +347,9 @@
             sp,
         );
 
-        // Check the `expn_info()` to see if this is a macro; if so, it's hard to
-        // extract the text and make a good suggestion, so don't bother.
-        let is_macro = sp.ctxt().outer_expn_info().is_some();
+        // If the span is from a macro, then it's hard to extract the text
+        // and make a good suggestion, so don't bother.
+        let is_macro = sp.from_expansion();
 
         match (&expr.node, &expected.sty, &checked_ty.sty) {
             (_, &ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (&exp.sty, &check.sty) {
@@ -554,6 +554,10 @@
             // FIXME(estebank): modify once we decide to suggest `as` casts
             return false;
         }
+        if !self.tcx.sess.source_map().span_to_filename(expr.span).is_real() {
+            // Ignore if span is from within a macro.
+            return false;
+        }
 
         // If casting this expression to a given numeric type would be appropriate in case of a type
         // mismatch.
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index 9680f61..d139cd4 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -24,6 +24,7 @@
 use syntax::util::lev_distance::find_best_match_for_name;
 use rustc::hir;
 use rustc::hir::{ExprKind, QPath};
+use rustc::hir::def_id::DefId;
 use rustc::hir::def::{CtorKind, Res, DefKind};
 use rustc::hir::ptr::P;
 use rustc::infer;
@@ -1336,114 +1337,180 @@
         autoderef.unambiguous_final_ty(self);
 
         if let Some((did, field_ty)) = private_candidate {
-            let struct_path = self.tcx().def_path_str(did);
-            let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
-                                           "field `{}` of struct `{}` is private",
-                                           field, struct_path);
-            // Also check if an accessible method exists, which is often what is meant.
-            if self.method_exists(field, expr_t, expr.hir_id, false)
-                && !self.expr_in_place(expr.hir_id)
-            {
-                self.suggest_method_call(
-                    &mut err,
-                    &format!("a method `{}` also exists, call it with parentheses", field),
-                    field,
-                    expr_t,
-                    expr.hir_id,
-                );
-            }
-            err.emit();
-            field_ty
-        } else if field.name == kw::Invalid {
-            self.tcx().types.err
-        } else if self.method_exists(field, expr_t, expr.hir_id, true) {
-            let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
-                               "attempted to take value of method `{}` on type `{}`",
-                               field, expr_t);
-
-            if !self.expr_in_place(expr.hir_id) {
-                self.suggest_method_call(
-                    &mut err,
-                    "use parentheses to call the method",
-                    field,
-                    expr_t,
-                    expr.hir_id
-                );
-            } else {
-                err.help("methods are immutable and cannot be assigned to");
-            }
-
-            err.emit();
-            self.tcx().types.err
-        } else {
-            if !expr_t.is_primitive_ty() {
-                let mut err = self.no_such_field_err(field.span, field, expr_t);
-
-                match expr_t.sty {
-                    ty::Adt(def, _) if !def.is_enum() => {
-                        if let Some(suggested_field_name) =
-                            Self::suggest_field_name(def.non_enum_variant(),
-                                                     &field.as_str(), vec![]) {
-                                err.span_suggestion(
-                                    field.span,
-                                    "a field with a similar name exists",
-                                    suggested_field_name.to_string(),
-                                    Applicability::MaybeIncorrect,
-                                );
-                            } else {
-                                err.span_label(field.span, "unknown field");
-                                let struct_variant_def = def.non_enum_variant();
-                                let field_names = self.available_field_names(struct_variant_def);
-                                if !field_names.is_empty() {
-                                    err.note(&format!("available fields are: {}",
-                                                      self.name_series_display(field_names)));
-                                }
-                            };
-                    }
-                    ty::Array(_, len) => {
-                        if let (Some(len), Ok(user_index)) = (
-                            len.try_eval_usize(self.tcx, self.param_env),
-                            field.as_str().parse::<u64>()
-                        ) {
-                            let base = self.tcx.sess.source_map()
-                                .span_to_snippet(base.span)
-                                .unwrap_or_else(|_|
-                                    self.tcx.hir().hir_to_pretty_string(base.hir_id));
-                            let help = "instead of using tuple indexing, use array indexing";
-                            let suggestion = format!("{}[{}]", base, field);
-                            let applicability = if len < user_index {
-                                Applicability::MachineApplicable
-                            } else {
-                                Applicability::MaybeIncorrect
-                            };
-                            err.span_suggestion(
-                                expr.span, help, suggestion, applicability
-                            );
-                        }
-                    }
-                    ty::RawPtr(..) => {
-                        let base = self.tcx.sess.source_map()
-                            .span_to_snippet(base.span)
-                            .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
-                        let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
-                        let suggestion = format!("(*{}).{}", base, field);
-                        err.span_suggestion(
-                            expr.span,
-                            &msg,
-                            suggestion,
-                            Applicability::MaybeIncorrect,
-                        );
-                    }
-                    _ => {}
-                }
-                err
-            } else {
-                type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
-                                   "`{}` is a primitive type and therefore doesn't have fields",
-                                   expr_t)
-            }.emit();
-            self.tcx().types.err
+            self.ban_private_field_access(expr, expr_t, field, did);
+            return field_ty;
         }
+
+        if field.name == kw::Invalid {
+        } else if self.method_exists(field, expr_t, expr.hir_id, true) {
+            self.ban_take_value_of_method(expr, expr_t, field);
+        } else if !expr_t.is_primitive_ty() {
+            let mut err = self.no_such_field_err(field.span, field, expr_t);
+
+            match expr_t.sty {
+                ty::Adt(def, _) if !def.is_enum() => {
+                    self.suggest_fields_on_recordish(&mut err, def, field);
+                }
+                ty::Array(_, len) => {
+                    self.maybe_suggest_array_indexing(&mut err, expr, base, field, len);
+                }
+                ty::RawPtr(..) => {
+                    self.suggest_first_deref_field(&mut err, expr, base, field);
+                }
+                _ => {}
+            }
+
+            if field.name == kw::Await {
+                // We know by construction that `<expr>.await` is either on Rust 2015
+                // or results in `ExprKind::Await`. Suggest switching the edition to 2018.
+                err.note("to `.await` a `Future`, switch to Rust 2018");
+                err.help("set `edition = \"2018\"` in `Cargo.toml`");
+                err.note("for more on editions, read https://doc.rust-lang.org/edition-guide");
+            }
+
+            err.emit();
+        } else {
+            type_error_struct!(
+                self.tcx().sess,
+                field.span,
+                expr_t,
+                E0610,
+                "`{}` is a primitive type and therefore doesn't have fields",
+                expr_t
+            )
+            .emit();
+        }
+
+        self.tcx().types.err
+    }
+
+    fn ban_private_field_access(
+        &self,
+        expr: &hir::Expr,
+        expr_t: Ty<'tcx>,
+        field: ast::Ident,
+        base_did: DefId,
+    ) {
+        let struct_path = self.tcx().def_path_str(base_did);
+        let mut err = struct_span_err!(
+            self.tcx().sess,
+            expr.span,
+            E0616,
+            "field `{}` of struct `{}` is private",
+            field,
+            struct_path
+        );
+        // Also check if an accessible method exists, which is often what is meant.
+        if self.method_exists(field, expr_t, expr.hir_id, false)
+            && !self.expr_in_place(expr.hir_id)
+        {
+            self.suggest_method_call(
+                &mut err,
+                &format!("a method `{}` also exists, call it with parentheses", field),
+                field,
+                expr_t,
+                expr.hir_id,
+            );
+        }
+        err.emit();
+    }
+
+    fn ban_take_value_of_method(&self, expr: &hir::Expr, expr_t: Ty<'tcx>, field: ast::Ident) {
+        let mut err = type_error_struct!(
+            self.tcx().sess,
+            field.span,
+            expr_t,
+            E0615,
+            "attempted to take value of method `{}` on type `{}`",
+            field,
+            expr_t
+        );
+
+        if !self.expr_in_place(expr.hir_id) {
+            self.suggest_method_call(
+                &mut err,
+                "use parentheses to call the method",
+                field,
+                expr_t,
+                expr.hir_id
+            );
+        } else {
+            err.help("methods are immutable and cannot be assigned to");
+        }
+
+        err.emit();
+    }
+
+    fn suggest_fields_on_recordish(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        def: &'tcx ty::AdtDef,
+        field: ast::Ident,
+    ) {
+        if let Some(suggested_field_name) =
+            Self::suggest_field_name(def.non_enum_variant(), &field.as_str(), vec![])
+        {
+            err.span_suggestion(
+                field.span,
+                "a field with a similar name exists",
+                suggested_field_name.to_string(),
+                Applicability::MaybeIncorrect,
+            );
+        } else {
+            err.span_label(field.span, "unknown field");
+            let struct_variant_def = def.non_enum_variant();
+            let field_names = self.available_field_names(struct_variant_def);
+            if !field_names.is_empty() {
+                err.note(&format!("available fields are: {}",
+                                    self.name_series_display(field_names)));
+            }
+        }
+    }
+
+    fn maybe_suggest_array_indexing(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        expr: &hir::Expr,
+        base: &hir::Expr,
+        field: ast::Ident,
+        len: &ty::Const<'tcx>,
+    ) {
+        if let (Some(len), Ok(user_index)) = (
+            len.try_eval_usize(self.tcx, self.param_env),
+            field.as_str().parse::<u64>()
+        ) {
+            let base = self.tcx.sess.source_map()
+                .span_to_snippet(base.span)
+                .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
+            let help = "instead of using tuple indexing, use array indexing";
+            let suggestion = format!("{}[{}]", base, field);
+            let applicability = if len < user_index {
+                Applicability::MachineApplicable
+            } else {
+                Applicability::MaybeIncorrect
+            };
+            err.span_suggestion(expr.span, help, suggestion, applicability);
+        }
+    }
+
+    fn suggest_first_deref_field(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        expr: &hir::Expr,
+        base: &hir::Expr,
+        field: ast::Ident,
+    ) {
+        let base = self.tcx.sess.source_map()
+            .span_to_snippet(base.span)
+            .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
+        let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
+        let suggestion = format!("(*{}).{}", base, field);
+        err.span_suggestion(
+            expr.span,
+            &msg,
+            suggestion,
+            Applicability::MaybeIncorrect,
+        );
     }
 
     fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 8bb24ee..dfbf8bc 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -67,7 +67,7 @@
     match intrinsic {
         "size_of" | "min_align_of" | "needs_drop" |
         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" |
-        "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
+        "wrapping_add" | "wrapping_sub" | "wrapping_mul" |
         "saturating_add" | "saturating_sub" |
         "rotate_left" | "rotate_right" |
         "ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse" |
@@ -314,7 +314,7 @@
                 (1, vec![param(0), param(0)], param(0)),
             "unchecked_add" | "unchecked_sub" | "unchecked_mul" =>
                 (1, vec![param(0), param(0)], param(0)),
-            "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
+            "wrapping_add" | "wrapping_sub" | "wrapping_mul" =>
                 (1, vec![param(0), param(0)], param(0)),
             "saturating_add" | "saturating_sub" =>
                 (1, vec![param(0), param(0)], param(0)),
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 4a5eba1..53024d9 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -985,7 +985,7 @@
                 hir::ItemKind::Use(..) => {
                     // Don't suggest placing a `use` before the prelude
                     // import or other generated ones.
-                    if item.span.ctxt().outer_expn_info().is_none() {
+                    if !item.span.from_expansion() {
                         self.span = Some(item.span.shrink_to_lo());
                         self.found_use = true;
                         return;
@@ -995,7 +995,7 @@
                 hir::ItemKind::ExternCrate(_) => {}
                 // ...but do place them before the first other item.
                 _ => if self.span.map_or(true, |span| item.span < span ) {
-                    if item.span.ctxt().outer_expn_info().is_none() {
+                    if !item.span.from_expansion() {
                         // Don't insert between attributes and an item.
                         if item.attrs.is_empty() {
                             self.span = Some(item.span.shrink_to_lo());
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 92f8fb3..fc1ee64 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2943,7 +2943,7 @@
             (PlaceOp::Index, false) => (self.tcx.lang_items().index_trait(), sym::index),
             (PlaceOp::Index, true) => (self.tcx.lang_items().index_mut_trait(), sym::index_mut),
         };
-        (tr, ast::Ident::with_empty_ctxt(name))
+        (tr, ast::Ident::with_dummy_span(name))
     }
 
     fn try_overloaded_place_op(&self,
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index b2c0e34..28a1ccd 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -203,7 +203,6 @@
                 fcx.register_wf_obligation(ty, span, code.clone());
             }
             ty::AssocKind::Method => {
-                reject_shadowing_parameters(fcx.tcx, item.def_id);
                 let sig = fcx.tcx.fn_sig(item.def_id);
                 let sig = fcx.normalize_associated_types_in(span, &sig);
                 check_fn_or_method(tcx, fcx, span, sig,
@@ -998,34 +997,6 @@
     err.emit();
 }
 
-fn reject_shadowing_parameters(tcx: TyCtxt<'_>, def_id: DefId) {
-    let generics = tcx.generics_of(def_id);
-    let parent = tcx.generics_of(generics.parent.unwrap());
-    let impl_params: FxHashMap<_, _> = parent.params.iter().flat_map(|param| match param.kind {
-        GenericParamDefKind::Lifetime => None,
-        GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => {
-            Some((param.name, param.def_id))
-        }
-    }).collect();
-
-    for method_param in &generics.params {
-        // Shadowing is checked in `resolve_lifetime`.
-        if let GenericParamDefKind::Lifetime = method_param.kind {
-            continue
-        }
-        if impl_params.contains_key(&method_param.name) {
-            // Tighten up the span to focus on only the shadowing type.
-            let type_span = tcx.def_span(method_param.def_id);
-
-            // The expectation here is that the original trait declaration is
-            // local so it should be okay to just unwrap everything.
-            let trait_def_id = impl_params[&method_param.name];
-            let trait_decl_span = tcx.def_span(trait_def_id);
-            error_194(tcx, type_span, trait_decl_span, &method_param.name.as_str()[..]);
-        }
-    }
-}
-
 /// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that
 /// aren't true.
 fn check_false_global_bounds(fcx: &FnCtxt<'_, '_>, span: Span, id: hir::HirId) {
@@ -1152,12 +1123,3 @@
     err.span_label(span, "unused parameter");
     err
 }
-
-fn error_194(tcx: TyCtxt<'_>, span: Span, trait_decl_span: Span, name: &str) {
-    struct_span_err!(tcx.sess, span, E0194,
-                     "type parameter `{}` shadows another type parameter of the same name",
-                     name)
-        .span_label(span, "shadows another type parameter")
-        .span_label(trait_decl_span, format!("first `{}` declared here", name))
-        .emit();
-}
diff --git a/src/librustc_typeck/error_codes.rs b/src/librustc_typeck/error_codes.rs
index 90118a9..ca9ce3d 100644
--- a/src/librustc_typeck/error_codes.rs
+++ b/src/librustc_typeck/error_codes.rs
@@ -1718,22 +1718,6 @@
 reason to also specify it in a `where` clause.
 "##,
 
-E0194: r##"
-A type parameter was declared which shadows an existing one. An example of this
-error:
-
-```compile_fail,E0194
-trait Foo<T> {
-    fn do_something(&self) -> T;
-    fn do_something_else<T: Clone>(&self, bar: T);
-}
-```
-
-In this example, the trait `Foo` and the trait method `do_something_else` both
-define a type parameter `T`. This is not allowed: if the method wishes to
-define a type parameter, it must use a different name for it.
-"##,
-
 E0195: r##"
 Your method's lifetime parameters do not match the trait declaration.
 Erroneous code example:
@@ -4837,6 +4821,7 @@
 //  E0188, // can not cast an immutable reference to a mutable pointer
 //  E0189, // deprecated: can only cast a boxed pointer to a boxed object
 //  E0190, // deprecated: can only cast a &-pointer to an &-object
+//  E0194, // merged into E0403
 //  E0196, // cannot determine a type for this closure
     E0203, // type parameter has more than one relaxed default bound,
            // and only one is supported
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index d5becd2..fede9e9 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -930,7 +930,7 @@
             if attr.check_name(sym::enable) {
                 if let Some(feat) = attr.value_str() {
                     let meta = attr::mk_name_value_item_str(
-                        Ident::with_empty_ctxt(sym::target_feature), feat, DUMMY_SP
+                        Ident::with_dummy_span(sym::target_feature), feat, DUMMY_SP
                     );
                     if let Ok(feat_cfg) = Cfg::parse(&meta) {
                         cfg &= feat_cfg;
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 5c9fac7..c73c464 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -4,6 +4,7 @@
 use rustc::hir;
 use rustc::lint as lint;
 use rustc::ty;
+use rustc_resolve::ParentScope;
 use syntax;
 use syntax::ast::{self, Ident};
 use syntax::ext::base::SyntaxExtensionKind;
@@ -431,7 +432,7 @@
     let path = ast::Path::from_ident(Ident::from_str(path_str));
     cx.enter_resolver(|resolver| {
         if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
-            &path, None, &resolver.dummy_parent_scope(), false, false
+            &path, None, &ParentScope::module(resolver.graph_root), false, false
         ) {
             if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
                 return Some(res.map_id(|_| panic!("unexpected id")));
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 5334c4d..3288d0b 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -23,7 +23,7 @@
 compiler_builtins = { version = "0.1.16" }
 profiler_builtins = { path = "../libprofiler_builtins", optional = true }
 unwind = { path = "../libunwind" }
-hashbrown = { version = "0.4.0", features = ['rustc-dep-of-std'] }
+hashbrown = { version = "0.5.0", features = ['rustc-dep-of-std'] }
 
 [dependencies.backtrace]
 version = "0.3.34"
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 1e28ee8..a053898 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -6,7 +6,7 @@
 
 use crate::borrow::Borrow;
 use crate::cell::Cell;
-use crate::collections::CollectionAllocErr;
+use crate::collections::TryReserveError;
 use crate::fmt::{self, Debug};
 #[allow(deprecated)]
 use crate::hash::{BuildHasher, Hash, Hasher, SipHasher13};
@@ -588,7 +588,7 @@
     /// ```
     #[inline]
     #[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
-    pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> {
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.base
             .try_reserve(additional)
             .map_err(map_collection_alloc_err)
@@ -2542,10 +2542,13 @@
 }
 
 #[inline]
-fn map_collection_alloc_err(err: hashbrown::CollectionAllocErr) -> CollectionAllocErr {
+fn map_collection_alloc_err(err: hashbrown::CollectionAllocErr) -> TryReserveError {
     match err {
-        hashbrown::CollectionAllocErr::CapacityOverflow => CollectionAllocErr::CapacityOverflow,
-        hashbrown::CollectionAllocErr::AllocErr => CollectionAllocErr::AllocErr,
+        hashbrown::CollectionAllocErr::CapacityOverflow => TryReserveError::CapacityOverflow,
+        hashbrown::CollectionAllocErr::AllocErr { layout } => TryReserveError::AllocError {
+            layout,
+            non_exhaustive: (),
+        },
     }
 }
 
@@ -2605,7 +2608,7 @@
     use super::RandomState;
     use crate::cell::RefCell;
     use rand::{thread_rng, Rng};
-    use realstd::collections::CollectionAllocErr::*;
+    use realstd::collections::TryReserveError::*;
     use realstd::usize;
 
     // https://github.com/rust-lang/rust/issues/62301
@@ -3405,7 +3408,7 @@
             panic!("usize::MAX should trigger an overflow!");
         }
 
-        if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE / 8) {
+        if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE / 8) {
         } else {
             panic!("usize::MAX / 8 should trigger an OOM!")
         }
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index d243412..26db651 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -1,5 +1,5 @@
 use crate::borrow::Borrow;
-use crate::collections::CollectionAllocErr;
+use crate::collections::TryReserveError;
 use crate::fmt;
 use crate::hash::{Hash, BuildHasher};
 use crate::iter::{Chain, FromIterator, FusedIterator};
@@ -383,7 +383,7 @@
     /// ```
     #[inline]
     #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-    pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> {
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
         self.map.try_reserve(additional)
     }
 
diff --git a/src/libstd/collections/mod.rs b/src/libstd/collections/mod.rs
index 15c2532..f595746 100644
--- a/src/libstd/collections/mod.rs
+++ b/src/libstd/collections/mod.rs
@@ -427,7 +427,7 @@
 pub use self::hash_set::HashSet;
 
 #[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
-pub use alloc_crate::collections::CollectionAllocErr;
+pub use alloc_crate::collections::TryReserveError;
 
 mod hash;
 
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 1f48315..c3882ba 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -228,7 +228,6 @@
 // std is implemented with unstable features, many of which are internal
 // compiler details that will never be stable
 // NB: the following list is sorted to minimize merge conflicts.
-#![feature(__rust_unstable_column)]
 #![feature(alloc_error_handler)]
 #![feature(alloc_layout_extra)]
 #![feature(allocator_api)]
@@ -251,6 +250,7 @@
 #![feature(concat_idents)]
 #![feature(const_cstr_unchecked)]
 #![feature(const_raw_ptr_deref)]
+#![feature(container_error_extra)]
 #![feature(core_intrinsics)]
 #![feature(custom_test_frameworks)]
 #![feature(doc_alias)]
@@ -550,7 +550,6 @@
     option_env,
     stringify,
     // Unstable
-    __rust_unstable_column,
     asm,
     concat_idents,
     format_args_nl,
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index f200093..cbeaf20 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -53,20 +53,20 @@
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable(__rust_unstable_column, libstd_sys_internals)]
+#[allow_internal_unstable(libstd_sys_internals)]
 macro_rules! panic {
     () => ({
         $crate::panic!("explicit panic")
     });
     ($msg:expr) => ({
-        $crate::rt::begin_panic($msg, &(file!(), line!(), __rust_unstable_column!()))
+        $crate::rt::begin_panic($msg, &($crate::file!(), $crate::line!(), $crate::column!()))
     });
     ($msg:expr,) => ({
         $crate::panic!($msg)
     });
     ($fmt:expr, $($arg:tt)+) => ({
-        $crate::rt::begin_panic_fmt(&format_args!($fmt, $($arg)+),
-                                    &(file!(), line!(), __rust_unstable_column!()))
+        $crate::rt::begin_panic_fmt(&$crate::format_args!($fmt, $($arg)+),
+                                    &($crate::file!(), $crate::line!(), $crate::column!()))
     });
 }
 
@@ -113,7 +113,7 @@
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow_internal_unstable(print_internals)]
 macro_rules! print {
-    ($($arg:tt)*) => ($crate::io::_print(format_args!($($arg)*)));
+    ($($arg:tt)*) => ($crate::io::_print($crate::format_args!($($arg)*)));
 }
 
 /// Prints to the standard output, with a newline.
@@ -147,7 +147,7 @@
 macro_rules! println {
     () => ($crate::print!("\n"));
     ($($arg:tt)*) => ({
-        $crate::io::_print(format_args_nl!($($arg)*));
+        $crate::io::_print($crate::format_args_nl!($($arg)*));
     })
 }
 
@@ -176,7 +176,7 @@
 #[stable(feature = "eprint", since = "1.19.0")]
 #[allow_internal_unstable(print_internals)]
 macro_rules! eprint {
-    ($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)));
+    ($($arg:tt)*) => ($crate::io::_eprint($crate::format_args!($($arg)*)));
 }
 
 /// Prints to the standard error, with a newline.
@@ -206,7 +206,7 @@
 macro_rules! eprintln {
     () => ($crate::eprint!("\n"));
     ($($arg:tt)*) => ({
-        $crate::io::_eprint(format_args_nl!($($arg)*));
+        $crate::io::_eprint($crate::format_args_nl!($($arg)*));
     })
 }
 
@@ -337,7 +337,7 @@
 #[stable(feature = "dbg_macro", since = "1.32.0")]
 macro_rules! dbg {
     () => {
-        $crate::eprintln!("[{}:{}]", file!(), line!());
+        $crate::eprintln!("[{}:{}]", $crate::file!(), $crate::line!());
     };
     ($val:expr) => {
         // Use of `match` here is intentional because it affects the lifetimes
@@ -345,7 +345,7 @@
         match $val {
             tmp => {
                 $crate::eprintln!("[{}:{}] {} = {:#?}",
-                    file!(), line!(), stringify!($val), &tmp);
+                    $crate::file!(), $crate::line!(), $crate::stringify!($val), &tmp);
                 tmp
             }
         }
diff --git a/src/libstd/prelude/v1.rs b/src/libstd/prelude/v1.rs
index 752c620..3e4cf91 100644
--- a/src/libstd/prelude/v1.rs
+++ b/src/libstd/prelude/v1.rs
@@ -40,7 +40,6 @@
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[doc(no_inline)]
 pub use core::prelude::v1::{
-    __rust_unstable_column,
     asm,
     assert,
     cfg,
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 3ae37f7..9091607 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -5,7 +5,7 @@
 pub use crate::symbol::{Ident, Symbol as Name};
 pub use crate::util::parser::ExprPrecedence;
 
-use crate::ext::hygiene::{ExpnId, SyntaxContext};
+use crate::ext::hygiene::ExpnId;
 use crate::parse::token::{self, DelimToken};
 use crate::print::pprust;
 use crate::ptr::P;
@@ -1782,7 +1782,6 @@
     pub volatile: bool,
     pub alignstack: bool,
     pub dialect: AsmDialect,
-    pub ctxt: SyntaxContext,
 }
 
 /// An argument in a function header.
@@ -2030,7 +2029,6 @@
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub struct GlobalAsm {
     pub asm: Symbol,
-    pub ctxt: SyntaxContext,
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index 85c661d..bcf03b5 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -327,7 +327,7 @@
         if self.is_sugared_doc {
             let comment = self.value_str().unwrap();
             let meta = mk_name_value_item_str(
-                Ident::with_empty_ctxt(sym::doc),
+                Ident::with_dummy_span(sym::doc),
                 Symbol::intern(&strip_doc_comment_decoration(&comment.as_str())),
                 DUMMY_SP,
             );
@@ -412,7 +412,7 @@
     Attribute {
         id: mk_attr_id(),
         style,
-        path: Path::from_ident(Ident::with_empty_ctxt(sym::doc).with_span_pos(span)),
+        path: Path::from_ident(Ident::with_dummy_span(sym::doc).with_span_pos(span)),
         tokens: MetaItemKind::NameValue(lit).tokens(span),
         is_sugared_doc: true,
         span,
diff --git a/src/libsyntax/diagnostics/plugin.rs b/src/libsyntax/diagnostics/plugin.rs
index 80591ad..9618b5a 100644
--- a/src/libsyntax/diagnostics/plugin.rs
+++ b/src/libsyntax/diagnostics/plugin.rs
@@ -172,7 +172,7 @@
             (descriptions.len(), ecx.expr_vec(span, descriptions))
         });
 
-    let static_ = ecx.lifetime(span, Ident::with_empty_ctxt(kw::StaticLifetime));
+    let static_ = ecx.lifetime(span, Ident::with_dummy_span(kw::StaticLifetime));
     let ty_str = ecx.ty_rptr(
         span,
         ecx.ty_ident(span, ecx.ident_of("str")),
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index edeca04..fb1bf4d 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -15,7 +15,7 @@
 use errors::{DiagnosticBuilder, DiagnosticId};
 use smallvec::{smallvec, SmallVec};
 use syntax_pos::{FileName, Span, MultiSpan, DUMMY_SP};
-use syntax_pos::hygiene::{ExpnInfo, ExpnKind};
+use syntax_pos::hygiene::{ExpnData, ExpnKind};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{self, Lrc};
@@ -640,10 +640,11 @@
         SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
     }
 
-    pub fn expn_info(&self, call_site: Span, descr: Symbol) -> ExpnInfo {
-        ExpnInfo {
-            call_site,
+    pub fn expn_data(&self, parent: ExpnId, call_site: Span, descr: Symbol) -> ExpnData {
+        ExpnData {
             kind: ExpnKind::Macro(self.macro_kind(), descr),
+            parent,
+            call_site,
             def_site: self.span,
             default_transparency: self.default_transparency,
             allow_internal_unstable: self.allow_internal_unstable.clone(),
@@ -707,7 +708,7 @@
 
 /// One of these is made during expansion and incrementally updated as we go;
 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
-/// -> expn_info` of their expansion context stored into their span.
+/// -> expn_data` of their expansion context stored into their span.
 pub struct ExtCtxt<'a> {
     pub parse_sess: &'a parse::ParseSess,
     pub ecfg: expand::ExpansionConfig<'a>,
@@ -756,13 +757,10 @@
     pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
     pub fn cfg(&self) -> &ast::CrateConfig { &self.parse_sess.config }
     pub fn call_site(&self) -> Span {
-        match self.current_expansion.id.expn_info() {
-            Some(expn_info) => expn_info.call_site,
-            None => DUMMY_SP,
-        }
+        self.current_expansion.id.expn_data().call_site
     }
     pub fn backtrace(&self) -> SyntaxContext {
-        SyntaxContext::empty().apply_mark(self.current_expansion.id)
+        SyntaxContext::root().apply_mark(self.current_expansion.id)
     }
 
     /// Returns span for the macro which originally caused the current expansion to happen.
@@ -772,17 +770,13 @@
         let mut ctxt = self.backtrace();
         let mut last_macro = None;
         loop {
-            if ctxt.outer_expn_info().map_or(None, |info| {
-                if info.kind.descr() == sym::include {
-                    // Stop going up the backtrace once include! is encountered
-                    return None;
-                }
-                ctxt = info.call_site.ctxt();
-                last_macro = Some(info.call_site);
-                Some(())
-            }).is_none() {
-                break
+            let expn_data = ctxt.outer_expn_data();
+            // Stop going up the backtrace once include! is encountered
+            if expn_data.is_root() || expn_data.kind.descr() == sym::include {
+                break;
             }
+            ctxt = expn_data.call_site.ctxt();
+            last_macro = Some(expn_data.call_site);
         }
         last_macro
     }
@@ -872,7 +866,7 @@
     pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
         let def_site = DUMMY_SP.apply_mark(self.current_expansion.id);
         iter::once(Ident::new(kw::DollarCrate, def_site))
-            .chain(components.iter().map(|&s| Ident::with_empty_ctxt(s)))
+            .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
             .collect()
     }
     pub fn name_of(&self, st: &str) -> ast::Name {
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 38f46ee..e2ac4d5 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -340,7 +340,7 @@
         self.expr_path(self.path_ident(span, id))
     }
     pub fn expr_self(&self, span: Span) -> P<ast::Expr> {
-        self.expr_ident(span, Ident::with_empty_ctxt(kw::SelfLower))
+        self.expr_ident(span, Ident::with_dummy_span(kw::SelfLower))
     }
 
     pub fn expr_binary(&self, sp: Span, op: ast::BinOpKind,
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9798394..dac4029 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -5,7 +5,7 @@
 use crate::config::StripUnconfigured;
 use crate::ext::base::*;
 use crate::ext::proc_macro::collect_derives;
-use crate::ext::hygiene::{ExpnId, SyntaxContext, ExpnInfo, ExpnKind};
+use crate::ext::hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind};
 use crate::ext::tt::macro_rules::annotate_err_with_kind;
 use crate::ext::placeholders::{placeholder, PlaceholderExpander};
 use crate::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
@@ -25,7 +25,6 @@
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
-use std::fs;
 use std::io::ErrorKind;
 use std::{iter, mem};
 use std::ops::DerefMut;
@@ -353,7 +352,7 @@
                 derives.reserve(traits.len());
                 invocations.reserve(traits.len());
                 for path in traits {
-                    let expn_id = ExpnId::fresh(self.cx.current_expansion.id, None);
+                    let expn_id = ExpnId::fresh(None);
                     derives.push(expn_id);
                     invocations.push(Invocation {
                         kind: InvocationKind::Derive { path, item: item.clone() },
@@ -475,11 +474,11 @@
         }
 
         if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
-            let info = self.cx.current_expansion.id.expn_info().unwrap();
+            let expn_data = self.cx.current_expansion.id.expn_data();
             let suggested_limit = self.cx.ecfg.recursion_limit * 2;
-            let mut err = self.cx.struct_span_err(info.call_site,
+            let mut err = self.cx.struct_span_err(expn_data.call_site,
                 &format!("recursion limit reached while expanding the macro `{}`",
-                         info.kind.descr()));
+                         expn_data.kind.descr()));
             err.help(&format!(
                 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
                 suggested_limit));
@@ -759,7 +758,7 @@
             let msg = format!("macro expansion ignores token `{}` and any following",
                               self.this_token_to_string());
             // Avoid emitting backtrace info twice.
-            let def_site_span = self.token.span.with_ctxt(SyntaxContext::empty());
+            let def_site_span = self.token.span.with_ctxt(SyntaxContext::root());
             let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
             err.span_label(span, "caused by the macro expansion here");
             let msg = format!(
@@ -796,17 +795,20 @@
 
 impl<'a, 'b> InvocationCollector<'a, 'b> {
     fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
-        // Expansion info for all the collected invocations is set upon their resolution,
+        // Expansion data for all the collected invocations is set upon their resolution,
         // with exception of the derive container case which is not resolved and can get
-        // its expansion info immediately.
-        let expn_info = match &kind {
-            InvocationKind::DeriveContainer { item, .. } => Some(ExpnInfo::default(
-                ExpnKind::Macro(MacroKind::Attr, sym::derive),
-                item.span(), self.cx.parse_sess.edition,
-            )),
+        // its expansion data immediately.
+        let expn_data = match &kind {
+            InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
+                parent: self.cx.current_expansion.id,
+                ..ExpnData::default(
+                    ExpnKind::Macro(MacroKind::Attr, sym::derive),
+                    item.span(), self.cx.parse_sess.edition,
+                )
+            }),
             _ => None,
         };
-        let expn_id = ExpnId::fresh(self.cx.current_expansion.id, expn_info);
+        let expn_id = ExpnId::fresh(expn_data);
         self.invocations.push(Invocation {
             kind,
             fragment_kind,
@@ -1238,32 +1240,30 @@
                     }
 
                     let filename = self.cx.resolve_path(&*file.as_str(), it.span());
-                    match fs::read_to_string(&filename) {
-                        Ok(src) => {
-                            let src_interned = Symbol::intern(&src);
-
-                            // Add this input file to the code map to make it available as
-                            // dependency information
-                            self.cx.source_map().new_source_file(filename.into(), src);
+                    match self.cx.source_map().load_file(&filename) {
+                        Ok(source_file) => {
+                            let src = source_file.src.as_ref()
+                                .expect("freshly loaded file should have a source");
+                            let src_interned = Symbol::intern(src.as_str());
 
                             let include_info = vec![
                                 ast::NestedMetaItem::MetaItem(
                                     attr::mk_name_value_item_str(
-                                        Ident::with_empty_ctxt(sym::file),
+                                        Ident::with_dummy_span(sym::file),
                                         file,
                                         DUMMY_SP,
                                     ),
                                 ),
                                 ast::NestedMetaItem::MetaItem(
                                     attr::mk_name_value_item_str(
-                                        Ident::with_empty_ctxt(sym::contents),
+                                        Ident::with_dummy_span(sym::contents),
                                         src_interned,
                                         DUMMY_SP,
                                     ),
                                 ),
                             ];
 
-                            let include_ident = Ident::with_empty_ctxt(sym::include);
+                            let include_ident = Ident::with_dummy_span(sym::include);
                             let item = attr::mk_list_item(include_ident, include_info);
                             items.push(ast::NestedMetaItem::MetaItem(item));
                         }
@@ -1325,7 +1325,7 @@
                 }
             }
 
-            let meta = attr::mk_list_item(Ident::with_empty_ctxt(sym::doc), items);
+            let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
             *at = attr::Attribute {
                 span: at.span,
                 id: at.id,
diff --git a/src/libsyntax/ext/proc_macro_server.rs b/src/libsyntax/ext/proc_macro_server.rs
index 36621ce..1619fa6 100644
--- a/src/libsyntax/ext/proc_macro_server.rs
+++ b/src/libsyntax/ext/proc_macro_server.rs
@@ -362,10 +362,10 @@
 impl<'a> Rustc<'a> {
     pub fn new(cx: &'a ExtCtxt<'_>) -> Self {
         // No way to determine def location for a proc macro right now, so use call location.
-        let location = cx.current_expansion.id.expn_info().unwrap().call_site;
+        let location = cx.current_expansion.id.expn_data().call_site;
         let to_span = |transparency| {
             location.with_ctxt(
-                SyntaxContext::empty()
+                SyntaxContext::root()
                     .apply_mark_with_transparency(cx.current_expansion.id, transparency),
             )
         };
@@ -677,7 +677,7 @@
         self.sess.source_map().lookup_char_pos(span.lo()).file
     }
     fn parent(&mut self, span: Self::Span) -> Option<Self::Span> {
-        span.ctxt().outer_expn_info().map(|i| i.call_site)
+        span.parent()
     }
     fn source(&mut self, span: Self::Span) -> Self::Span {
         span.source_callsite()
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 8a56ae1..1a87a90 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -30,7 +30,6 @@
 
 use errors::{Applicability, DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::sync::Lock;
 use rustc_target::spec::abi::Abi;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
 use log::debug;
@@ -2088,11 +2087,6 @@
                                        "type ascription is experimental");
                 }
             }
-            ast::ExprKind::Yield(..) => {
-                gate_feature_post!(&self, generators,
-                                  e.span,
-                                  "yield syntax is experimental");
-            }
             ast::ExprKind::TryBlock(_) => {
                 gate_feature_post!(&self, try_blocks, e.span, "`try` expression is experimental");
             }
@@ -2427,10 +2421,6 @@
     features
 }
 
-fn for_each_in_lock<T>(vec: &Lock<Vec<T>>, f: impl Fn(&T)) {
-    vec.borrow().iter().for_each(f);
-}
-
 pub fn check_crate(krate: &ast::Crate,
                    sess: &ParseSess,
                    features: &Features,
@@ -2443,26 +2433,16 @@
         plugin_attributes,
     };
 
-    for_each_in_lock(&sess.param_attr_spans, |span| gate_feature!(
-        &ctx,
-        param_attrs,
-        *span,
-        "attributes on function parameters are unstable"
-    ));
+    macro_rules! gate_all {
+        ($spans:ident, $gate:ident, $msg:literal) => {
+            for span in &*sess.$spans.borrow() { gate_feature!(&ctx, $gate, *span, $msg); }
+        }
+    }
 
-    for_each_in_lock(&sess.let_chains_spans, |span| gate_feature!(
-        &ctx,
-        let_chains,
-        *span,
-        "`let` expressions in this position are experimental"
-    ));
-
-    for_each_in_lock(&sess.async_closure_spans, |span| gate_feature!(
-        &ctx,
-        async_closure,
-        *span,
-        "async closures are unstable"
-    ));
+    gate_all!(param_attr_spans, param_attrs, "attributes on function parameters are unstable");
+    gate_all!(let_chains_spans, let_chains, "`let` expressions in this position are experimental");
+    gate_all!(async_closure_spans, async_closure, "async closures are unstable");
+    gate_all!(yield_spans, generators, "yield syntax is experimental");
 
     let visitor = &mut PostExpansionVisitor {
         context: &ctx,
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index acafe32..18d4a64 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -1182,7 +1182,7 @@
         }
         ExprKind::InlineAsm(asm) => {
             let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
-                            alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
+                            alignstack: _, dialect: _ } = asm.deref_mut();
             for out in outputs {
                 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
                 vis.visit_expr(expr);
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index e86d4c7..17629d3 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -4,7 +4,7 @@
 use crate::parse::unescape_error_reporting::{emit_unescape_error, push_escaped_char};
 
 use errors::{FatalError, DiagnosticBuilder};
-use syntax_pos::{BytePos, Pos, Span, NO_EXPANSION};
+use syntax_pos::{BytePos, Pos, Span};
 use rustc_lexer::Base;
 use rustc_lexer::unescape;
 
@@ -84,7 +84,7 @@
 
 
     fn mk_sp(&self, lo: BytePos, hi: BytePos) -> Span {
-        self.override_span.unwrap_or_else(|| Span::new(lo, hi, NO_EXPANSION))
+        self.override_span.unwrap_or_else(|| Span::with_root_ctxt(lo, hi))
     }
 
     /// Returns the next token, including trivia like whitespace or comments.
diff --git a/src/libsyntax/parse/lexer/tests.rs b/src/libsyntax/parse/lexer/tests.rs
index fc47e4f..9457014 100644
--- a/src/libsyntax/parse/lexer/tests.rs
+++ b/src/libsyntax/parse/lexer/tests.rs
@@ -1,41 +1,17 @@
 use super::*;
 
-use crate::ast::CrateConfig;
 use crate::symbol::Symbol;
 use crate::source_map::{SourceMap, FilePathMapping};
-use crate::feature_gate::UnstableFeatures;
 use crate::parse::token;
-use crate::diagnostics::plugin::ErrorMap;
 use crate::with_default_globals;
 use std::io;
 use std::path::PathBuf;
-use syntax_pos::{BytePos, Span, NO_EXPANSION, edition::Edition};
-use rustc_data_structures::fx::{FxHashSet, FxHashMap};
-use rustc_data_structures::sync::{Lock, Once};
+use errors::{Handler, emitter::EmitterWriter};
+use syntax_pos::{BytePos, Span};
 
 fn mk_sess(sm: Lrc<SourceMap>) -> ParseSess {
-    let emitter = errors::emitter::EmitterWriter::new(Box::new(io::sink()),
-                                                        Some(sm.clone()),
-                                                        false,
-                                                        false,
-                                                        false);
-    ParseSess {
-        span_diagnostic: errors::Handler::with_emitter(true, None, Box::new(emitter)),
-        unstable_features: UnstableFeatures::from_environment(),
-        config: CrateConfig::default(),
-        included_mod_stack: Lock::new(Vec::new()),
-        source_map: sm,
-        missing_fragment_specifiers: Lock::new(FxHashSet::default()),
-        raw_identifier_spans: Lock::new(Vec::new()),
-        registered_diagnostics: Lock::new(ErrorMap::new()),
-        buffered_lints: Lock::new(vec![]),
-        edition: Edition::from_session(),
-        ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
-        param_attr_spans: Lock::new(Vec::new()),
-        let_chains_spans: Lock::new(Vec::new()),
-        async_closure_spans: Lock::new(Vec::new()),
-        injected_crate_name: Once::new(),
-    }
+    let emitter = EmitterWriter::new(Box::new(io::sink()), Some(sm.clone()), false, false, false);
+    ParseSess::with_span_handler(Handler::with_emitter(true, None, Box::new(emitter)), sm)
 }
 
 // open a string reader for the given string
@@ -61,7 +37,7 @@
         let tok1 = string_reader.next_token();
         let tok2 = Token::new(
             mk_ident("fn"),
-            Span::new(BytePos(21), BytePos(23), NO_EXPANSION),
+            Span::with_root_ctxt(BytePos(21), BytePos(23)),
         );
         assert_eq!(tok1.kind, tok2.kind);
         assert_eq!(tok1.span, tok2.span);
@@ -71,7 +47,7 @@
         assert_eq!(string_reader.pos.clone(), BytePos(28));
         let tok4 = Token::new(
             mk_ident("main"),
-            Span::new(BytePos(24), BytePos(28), NO_EXPANSION),
+            Span::with_root_ctxt(BytePos(24), BytePos(28)),
         );
         assert_eq!(tok3.kind, tok4.kind);
         assert_eq!(tok3.span, tok4.span);
diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/libsyntax/parse/lexer/unicode_chars.rs
index eaa736c..525b421 100644
--- a/src/libsyntax/parse/lexer/unicode_chars.rs
+++ b/src/libsyntax/parse/lexer/unicode_chars.rs
@@ -3,7 +3,7 @@
 
 use super::StringReader;
 use errors::{Applicability, DiagnosticBuilder};
-use syntax_pos::{BytePos, Pos, Span, NO_EXPANSION, symbol::kw};
+use syntax_pos::{BytePos, Pos, Span, symbol::kw};
 use crate::parse::token;
 
 #[rustfmt::skip] // for line breaks
@@ -343,7 +343,7 @@
         None => return None,
     };
 
-    let span = Span::new(pos, pos + Pos::from_usize(ch.len_utf8()), NO_EXPANSION);
+    let span = Span::with_root_ctxt(pos, pos + Pos::from_usize(ch.len_utf8()));
 
     let (ascii_name, token) = match ASCII_ARRAY.iter().find(|&&(c, _, _)| c == ascii_char) {
         Some((_ascii_char, ascii_name, token)) => (ascii_name, token),
@@ -362,10 +362,9 @@
             ascii_char, ascii_name
         );
         err.span_suggestion(
-            Span::new(
+            Span::with_root_ctxt(
                 pos,
                 pos + Pos::from_usize('“'.len_utf8() + s.len() + '”'.len_utf8()),
-                NO_EXPANSION,
             ),
             &msg,
             format!("\"{}\"", s),
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 80aa7a3..9088f92 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -16,6 +16,7 @@
 use rustc_data_structures::sync::{Lrc, Lock, Once};
 use syntax_pos::{Span, SourceFile, FileName, MultiSpan};
 use syntax_pos::edition::Edition;
+use syntax_pos::hygiene::ExpnId;
 
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
 use std::borrow::Cow;
@@ -62,6 +63,8 @@
     pub let_chains_spans: Lock<Vec<Span>>,
     // Places where `async || ..` exprs were used and should be feature gated.
     pub async_closure_spans: Lock<Vec<Span>>,
+    // Places where `yield e?` exprs were used and should be feature gated.
+    pub yield_spans: Lock<Vec<Span>>,
     pub injected_crate_name: Once<Symbol>,
 }
 
@@ -86,11 +89,12 @@
             included_mod_stack: Lock::new(vec![]),
             source_map,
             buffered_lints: Lock::new(vec![]),
-            edition: Edition::from_session(),
+            edition: ExpnId::root().expn_data().edition,
             ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
             param_attr_spans: Lock::new(Vec::new()),
             let_chains_spans: Lock::new(Vec::new()),
             async_closure_spans: Lock::new(Vec::new()),
+            yield_spans: Lock::new(Vec::new()),
             injected_crate_name: Once::new(),
         }
     }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 2286e74..89725d8 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -13,7 +13,6 @@
 use crate::ast::{self, AttrStyle, Attribute, Arg, BindingMode, StrStyle, SelfKind};
 use crate::ast::{FnDecl, Ident, IsAsync, MacDelimiter, Mutability, TyKind};
 use crate::ast::{Visibility, VisibilityKind, Unsafety, CrateSugar};
-use crate::ext::hygiene::SyntaxContext;
 use crate::source_map::{self, respan};
 use crate::parse::{SeqSep, literal, token};
 use crate::parse::lexer::UnmatchedBrace;
@@ -1101,7 +1100,7 @@
 
     crate fn process_potential_macro_variable(&mut self) {
         self.token = match self.token.kind {
-            token::Dollar if self.token.span.ctxt() != SyntaxContext::empty() &&
+            token::Dollar if self.token.span.from_expansion() &&
                              self.look_ahead(1, |t| t.is_ident()) => {
                 self.bump();
                 let name = match self.token.kind {
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index f4b6a92..ccc6bd150 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -997,6 +997,9 @@
                     } else {
                         ex = ExprKind::Yield(None);
                     }
+
+                    let span = lo.to(hi);
+                    self.sess.yield_spans.borrow_mut().push(span);
                 } else if self.eat_keyword(kw::Let) {
                     return self.parse_let_expr(attrs);
                 } else if is_span_rust_2018 && self.eat_keyword(kw::Await) {
diff --git a/src/libsyntax/parse/parser/module.rs b/src/libsyntax/parse/parser/module.rs
index 58a7ffb..3f6f87b 100644
--- a/src/libsyntax/parse/parser/module.rs
+++ b/src/libsyntax/parse/parser/module.rs
@@ -60,7 +60,7 @@
                 // Record that we fetched the mod from an external file
                 if warn {
                     let attr = attr::mk_attr_outer(
-                        attr::mk_word_item(Ident::with_empty_ctxt(sym::warn_directory_ownership)));
+                        attr::mk_word_item(Ident::with_dummy_span(sym::warn_directory_ownership)));
                     attr::mark_known(&attr);
                     attrs.push(attr);
                 }
diff --git a/src/libsyntax/parse/tests.rs b/src/libsyntax/parse/tests.rs
index 9edc83a..6a789ef 100644
--- a/src/libsyntax/parse/tests.rs
+++ b/src/libsyntax/parse/tests.rs
@@ -12,7 +12,7 @@
 use crate::tests::{matches_codepattern, string_to_stream, with_error_checking_parse};
 use crate::tokenstream::{DelimSpan, TokenTree, TokenStream};
 use crate::with_default_globals;
-use syntax_pos::{Span, BytePos, Pos, NO_EXPANSION};
+use syntax_pos::{Span, BytePos, Pos};
 
 use std::path::PathBuf;
 
@@ -27,7 +27,7 @@
 
 // produce a syntax_pos::span
 fn sp(a: u32, b: u32) -> Span {
-    Span::new(BytePos(a), BytePos(b), NO_EXPANSION)
+    Span::with_root_ctxt(BytePos(a), BytePos(b))
 }
 
 /// Parse a string, return an expr
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 5955b91..8a70098 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -123,13 +123,13 @@
         // of the feature gate, so we fake them up here.
 
         // #![feature(prelude_import)]
-        let pi_nested = attr::mk_nested_word_item(ast::Ident::with_empty_ctxt(sym::prelude_import));
-        let list = attr::mk_list_item(ast::Ident::with_empty_ctxt(sym::feature), vec![pi_nested]);
+        let pi_nested = attr::mk_nested_word_item(ast::Ident::with_dummy_span(sym::prelude_import));
+        let list = attr::mk_list_item(ast::Ident::with_dummy_span(sym::feature), vec![pi_nested]);
         let fake_attr = attr::mk_attr_inner(list);
         s.print_attribute(&fake_attr);
 
         // #![no_std]
-        let no_std_meta = attr::mk_word_item(ast::Ident::with_empty_ctxt(sym::no_std));
+        let no_std_meta = attr::mk_word_item(ast::Ident::with_dummy_span(sym::no_std));
         let fake_attr = attr::mk_attr_inner(no_std_meta);
         s.print_attribute(&fake_attr);
     }
diff --git a/src/libsyntax/source_map.rs b/src/libsyntax/source_map.rs
index 74cab00..7190cfd 100644
--- a/src/libsyntax/source_map.rs
+++ b/src/libsyntax/source_map.rs
@@ -8,7 +8,7 @@
 //! information, source code snippets, etc.
 
 pub use syntax_pos::*;
-pub use syntax_pos::hygiene::{ExpnKind, ExpnInfo};
+pub use syntax_pos::hygiene::{ExpnKind, ExpnData};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::StableHasher;
@@ -29,14 +29,15 @@
 
 /// Returns the span itself if it doesn't come from a macro expansion,
 /// otherwise return the call site span up to the `enclosing_sp` by
-/// following the `expn_info` chain.
+/// following the `expn_data` chain.
 pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span {
-    let call_site1 = sp.ctxt().outer_expn_info().map(|ei| ei.call_site);
-    let call_site2 = enclosing_sp.ctxt().outer_expn_info().map(|ei| ei.call_site);
-    match (call_site1, call_site2) {
-        (None, _) => sp,
-        (Some(call_site1), Some(call_site2)) if call_site1 == call_site2 => sp,
-        (Some(call_site1), _) => original_sp(call_site1, enclosing_sp),
+    let expn_data1 = sp.ctxt().outer_expn_data();
+    let expn_data2 = enclosing_sp.ctxt().outer_expn_data();
+    if expn_data1.is_root() ||
+       !expn_data2.is_root() && expn_data1.call_site == expn_data2.call_site {
+        sp
+    } else {
+        original_sp(expn_data1.call_site, enclosing_sp)
     }
 }
 
@@ -170,6 +171,26 @@
         Ok(self.new_source_file(filename, src))
     }
 
+    /// Loads source file as a binary blob.
+    ///
+    /// Unlike `load_file`, guarantees that no normalization like BOM-removal
+    /// takes place.
+    pub fn load_binary_file(&self, path: &Path) -> io::Result<Vec<u8>> {
+        // Ideally, this should use `self.file_loader`, but it can't
+        // deal with binary files yet.
+        let bytes = fs::read(path)?;
+
+        // We need to add file to the `SourceMap`, so that it is present
+        // in dep-info. There's also an edge case that file might be both
+        // loaded as a binary via `include_bytes!` and as proper `SourceFile`
+        // via `mod`, so we try to use real file contents and not just an
+        // empty string.
+        let text = std::str::from_utf8(&bytes).unwrap_or("")
+            .to_string();
+        self.new_source_file(path.to_owned().into(), text);
+        Ok(bytes)
+    }
+
     pub fn files(&self) -> MappedLockGuard<'_, Vec<Lrc<SourceFile>>> {
         LockGuard::map(self.files.borrow(), |files| &mut files.source_files)
     }
diff --git a/src/libsyntax/source_map/tests.rs b/src/libsyntax/source_map/tests.rs
index 427e86b..c7b8332 100644
--- a/src/libsyntax/source_map/tests.rs
+++ b/src/libsyntax/source_map/tests.rs
@@ -91,7 +91,7 @@
 fn t7() {
     // Test span_to_lines for a span ending at the end of source_file
     let sm = init_source_map();
-    let span = Span::new(BytePos(12), BytePos(23), NO_EXPANSION);
+    let span = Span::with_root_ctxt(BytePos(12), BytePos(23));
     let file_lines = sm.span_to_lines(span).unwrap();
 
     assert_eq!(file_lines.file.name, PathBuf::from("blork.rs").into());
@@ -107,7 +107,7 @@
     assert_eq!(input.len(), selection.len());
     let left_index = selection.find('~').unwrap() as u32;
     let right_index = selection.rfind('~').map(|x|x as u32).unwrap_or(left_index);
-    Span::new(BytePos(left_index), BytePos(right_index + 1), NO_EXPANSION)
+    Span::with_root_ctxt(BytePos(left_index), BytePos(right_index + 1))
 }
 
 /// Tests span_to_snippet and span_to_lines for a span converting 3
@@ -137,7 +137,7 @@
 fn t8() {
     // Test span_to_snippet for a span ending at the end of source_file
     let sm = init_source_map();
-    let span = Span::new(BytePos(12), BytePos(23), NO_EXPANSION);
+    let span = Span::with_root_ctxt(BytePos(12), BytePos(23));
     let snippet = sm.span_to_snippet(span);
 
     assert_eq!(snippet, Ok("second line".to_string()));
@@ -147,7 +147,7 @@
 fn t9() {
     // Test span_to_str for a span ending at the end of source_file
     let sm = init_source_map();
-    let span = Span::new(BytePos(12), BytePos(23), NO_EXPANSION);
+    let span = Span::with_root_ctxt(BytePos(12), BytePos(23));
     let sstr =  sm.span_to_string(span);
 
     assert_eq!(sstr, "blork.rs:2:1: 2:12");
@@ -198,10 +198,9 @@
             let lo = hi + offset;
             hi = lo + substring.len();
             if i == n {
-                let span = Span::new(
+                let span = Span::with_root_ctxt(
                     BytePos(lo as u32 + file.start_pos.0),
                     BytePos(hi as u32 + file.start_pos.0),
-                    NO_EXPANSION,
                 );
                 assert_eq!(&self.span_to_snippet(span).unwrap()[..],
                         substring);
diff --git a/src/libsyntax/tests.rs b/src/libsyntax/tests.rs
index cff034f..4c0e1e3 100644
--- a/src/libsyntax/tests.rs
+++ b/src/libsyntax/tests.rs
@@ -9,7 +9,7 @@
 use errors::emitter::EmitterWriter;
 use errors::Handler;
 use rustc_data_structures::sync::Lrc;
-use syntax_pos::{BytePos, NO_EXPANSION, Span, MultiSpan};
+use syntax_pos::{BytePos, Span, MultiSpan};
 
 use std::io;
 use std::io::prelude::*;
@@ -169,7 +169,7 @@
     let start = make_pos(file_text, start);
     let end = make_pos(file_text, end) + end.string.len(); // just after matching thing ends
     assert!(start <= end);
-    Span::new(BytePos(start as u32), BytePos(end as u32), NO_EXPANSION)
+    Span::with_root_ctxt(BytePos(start as u32), BytePos(end as u32))
 }
 
 fn make_pos(file_text: &str, pos: &Position) -> usize {
diff --git a/src/libsyntax/tokenstream/tests.rs b/src/libsyntax/tokenstream/tests.rs
index 72e22a4..5017e5f 100644
--- a/src/libsyntax/tokenstream/tests.rs
+++ b/src/libsyntax/tokenstream/tests.rs
@@ -3,14 +3,14 @@
 use crate::ast::Name;
 use crate::with_default_globals;
 use crate::tests::string_to_stream;
-use syntax_pos::{Span, BytePos, NO_EXPANSION};
+use syntax_pos::{Span, BytePos};
 
 fn string_to_ts(string: &str) -> TokenStream {
     string_to_stream(string.to_owned())
 }
 
 fn sp(a: u32, b: u32) -> Span {
-    Span::new(BytePos(a), BytePos(b), NO_EXPANSION)
+    Span::with_root_ctxt(BytePos(a), BytePos(b))
 }
 
 #[test]
diff --git a/src/libsyntax_ext/asm.rs b/src/libsyntax_ext/asm.rs
index 950166f..644a44f 100644
--- a/src/libsyntax_ext/asm.rs
+++ b/src/libsyntax_ext/asm.rs
@@ -63,7 +63,7 @@
     MacEager::expr(P(ast::Expr {
         id: ast::DUMMY_NODE_ID,
         node: ast::ExprKind::InlineAsm(P(inline_asm)),
-        span: sp,
+        span: sp.with_ctxt(cx.backtrace()),
         attrs: ThinVec::new(),
     }))
 }
@@ -277,6 +277,5 @@
         volatile,
         alignstack,
         dialect,
-        ctxt: cx.backtrace(),
     }))
 }
diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
index d80da56..d030ea4 100644
--- a/src/libsyntax_ext/deriving/clone.rs
+++ b/src/libsyntax_ext/deriving/clone.rs
@@ -35,7 +35,7 @@
             match annitem.node {
                 ItemKind::Struct(_, Generics { ref params, .. }) |
                 ItemKind::Enum(_, Generics { ref params, .. }) => {
-                    let container_id = cx.current_expansion.id.parent();
+                    let container_id = cx.current_expansion.id.expn_data().parent;
                     if cx.resolver.has_derives(container_id, SpecialDerives::COPY) &&
                         !params.iter().any(|param| match param.kind {
                             ast::GenericParamKind::Type { .. } => true,
@@ -129,7 +129,7 @@
     if is_union {
         // let _: AssertParamIsCopy<Self>;
         let self_ty =
-            cx.ty_path(cx.path_ident(trait_span, ast::Ident::with_empty_ctxt(kw::SelfUpper)));
+            cx.ty_path(cx.path_ident(trait_span, ast::Ident::with_dummy_span(kw::SelfUpper)));
         assert_ty_bounds(cx, &mut stmts, self_ty, trait_span, "AssertParamIsCopy");
     } else {
         match *substr.fields {
diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
index 5d7c4a8..54027c6 100644
--- a/src/libsyntax_ext/deriving/cmp/eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -13,7 +13,7 @@
                           mitem: &MetaItem,
                           item: &Annotatable,
                           push: &mut dyn FnMut(Annotatable)) {
-    cx.resolver.add_derives(cx.current_expansion.id.parent(), SpecialDerives::EQ);
+    cx.resolver.add_derives(cx.current_expansion.id.expn_data().parent, SpecialDerives::EQ);
 
     let inline = cx.meta_word(span, sym::inline);
     let hidden = cx.meta_list_item_word(span, sym::hidden);
diff --git a/src/libsyntax_ext/deriving/cmp/ord.rs b/src/libsyntax_ext/deriving/cmp/ord.rs
index 885cfee..55687c3 100644
--- a/src/libsyntax_ext/deriving/cmp/ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/ord.rs
@@ -43,17 +43,18 @@
 }
 
 
-pub fn ordering_collapsed(cx: &mut ExtCtxt<'_>,
-                          span: Span,
-                          self_arg_tags: &[ast::Ident])
-                          -> P<ast::Expr> {
+pub fn ordering_collapsed(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    self_arg_tags: &[ast::Ident],
+) -> P<ast::Expr> {
     let lft = cx.expr_ident(span, self_arg_tags[0]);
     let rgt = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[1]));
-    cx.expr_method_call(span, lft, cx.ident_of("cmp"), vec![rgt])
+    cx.expr_method_call(span, lft, ast::Ident::new(sym::cmp, span), vec![rgt])
 }
 
 pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
-    let test_id = cx.ident_of("cmp").gensym();
+    let test_id = ast::Ident::new(sym::cmp, span);
     let equals_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
 
     let cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
@@ -75,34 +76,34 @@
             // as the outermost one, and the last as the innermost.
             false,
             |cx, span, old, self_f, other_fs| {
-        // match new {
-        //     ::std::cmp::Ordering::Equal => old,
-        //     cmp => cmp
-        // }
+                // match new {
+                //     ::std::cmp::Ordering::Equal => old,
+                //     cmp => cmp
+                // }
 
-        let new = {
-            let other_f = match other_fs {
-                [o_f] => o_f,
-                _ => cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`"),
-            };
+                let new = {
+                    let other_f = match other_fs {
+                        [o_f] => o_f,
+                        _ => cx.span_bug(span, "not exactly 2 arguments in `derive(Ord)`"),
+                    };
 
-            let args = vec![
-                    cx.expr_addr_of(span, self_f),
-                    cx.expr_addr_of(span, other_f.clone()),
-                ];
+                    let args = vec![
+                            cx.expr_addr_of(span, self_f),
+                            cx.expr_addr_of(span, other_f.clone()),
+                        ];
 
-            cx.expr_call_global(span, cmp_path.clone(), args)
-        };
+                    cx.expr_call_global(span, cmp_path.clone(), args)
+                };
 
-        let eq_arm = cx.arm(span,
-                            vec![cx.pat_path(span, equals_path.clone())],
-                            old);
-        let neq_arm = cx.arm(span,
-                             vec![cx.pat_ident(span, test_id)],
-                             cx.expr_ident(span, test_id));
+                let eq_arm = cx.arm(span,
+                                    vec![cx.pat_path(span, equals_path.clone())],
+                                    old);
+                let neq_arm = cx.arm(span,
+                                     vec![cx.pat_ident(span, test_id)],
+                                     cx.expr_ident(span, test_id));
 
-        cx.expr_match(span, new, vec![eq_arm, neq_arm])
-    },
+                cx.expr_match(span, new, vec![eq_arm, neq_arm])
+            },
             cx.expr_path(equals_path.clone()),
             Box::new(|cx, span, (self_args, tag_tuple), _non_self_args| {
         if self_args.len() != 2 {
diff --git a/src/libsyntax_ext/deriving/cmp/partial_eq.rs b/src/libsyntax_ext/deriving/cmp/partial_eq.rs
index 7d7c4ae..91e1e80 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_eq.rs
@@ -13,7 +13,7 @@
                                   mitem: &MetaItem,
                                   item: &Annotatable,
                                   push: &mut dyn FnMut(Annotatable)) {
-    cx.resolver.add_derives(cx.current_expansion.id.parent(), SpecialDerives::PARTIAL_EQ);
+    cx.resolver.add_derives(cx.current_expansion.id.expn_data().parent, SpecialDerives::PARTIAL_EQ);
 
     // structures are equal if all fields are equal, and non equal, if
     // any fields are not equal or if the enum variants are different
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
index 0ec30f5..740b92a 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -94,11 +94,12 @@
     GeOp,
 }
 
-pub fn some_ordering_collapsed(cx: &mut ExtCtxt<'_>,
-                               span: Span,
-                               op: OrderingOp,
-                               self_arg_tags: &[ast::Ident])
-                               -> P<ast::Expr> {
+pub fn some_ordering_collapsed(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    op: OrderingOp,
+    self_arg_tags: &[ast::Ident],
+) -> P<ast::Expr> {
     let lft = cx.expr_ident(span, self_arg_tags[0]);
     let rgt = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[1]));
     let op_str = match op {
@@ -108,11 +109,11 @@
         GtOp => "gt",
         GeOp => "ge",
     };
-    cx.expr_method_call(span, lft, cx.ident_of(op_str), vec![rgt])
+    cx.expr_method_call(span, lft, ast::Ident::from_str_and_span(op_str, span), vec![rgt])
 }
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
-    let test_id = cx.ident_of("cmp").gensym();
+    let test_id = ast::Ident::new(sym::cmp, span);
     let ordering = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
     let ordering_expr = cx.expr_path(ordering.clone());
     let equals_expr = cx.expr_some(span, ordering_expr);
diff --git a/src/libsyntax_ext/deriving/debug.rs b/src/libsyntax_ext/deriving/debug.rs
index 15e93f2..4415354 100644
--- a/src/libsyntax_ext/deriving/debug.rs
+++ b/src/libsyntax_ext/deriving/debug.rs
@@ -62,7 +62,7 @@
     // We want to make sure we have the ctxt set so that we can use unstable methods
     let span = span.with_ctxt(cx.backtrace());
     let name = cx.expr_lit(span, ast::LitKind::Str(ident.name, ast::StrStyle::Cooked));
-    let builder = Ident::from_str("debug_trait_builder").gensym();
+    let builder = Ident::from_str_and_span("debug_trait_builder", span);
     let builder_expr = cx.expr_ident(span, builder.clone());
 
     let fmt = substr.nonself_args[0].clone();
@@ -73,7 +73,7 @@
             // tuple struct/"normal" variant
             let expr =
                 cx.expr_method_call(span, fmt, Ident::from_str("debug_tuple"), vec![name]);
-            stmts.push(cx.stmt_let(DUMMY_SP, true, builder, expr));
+            stmts.push(cx.stmt_let(span, true, builder, expr));
 
             for field in fields {
                 // Use double indirection to make sure this works for unsized types
@@ -82,7 +82,7 @@
 
                 let expr = cx.expr_method_call(span,
                                                 builder_expr.clone(),
-                                                Ident::with_empty_ctxt(sym::field),
+                                                Ident::new(sym::field, span),
                                                 vec![field]);
 
                 // Use `let _ = expr;` to avoid triggering the
@@ -106,7 +106,7 @@
                 let field = cx.expr_addr_of(field.span, field);
                 let expr = cx.expr_method_call(span,
                                                 builder_expr.clone(),
-                                                Ident::with_empty_ctxt(sym::field),
+                                                Ident::new(sym::field, span),
                                                 vec![name, field]);
                 stmts.push(stmt_let_undescore(cx, span, expr));
             }
diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs
index 293c5a1..9b6f851 100644
--- a/src/libsyntax_ext/deriving/decodable.rs
+++ b/src/libsyntax_ext/deriving/decodable.rs
@@ -1,6 +1,6 @@
-//! The compiler code necessary for `#[derive(Decodable)]`. See encodable.rs for more.
+//! The compiler code necessary for `#[derive(RustcDecodable)]`. See encodable.rs for more.
 
-use crate::deriving::{self, pathvec_std};
+use crate::deriving::pathvec_std;
 use crate::deriving::generic::*;
 use crate::deriving::generic::ty::*;
 
@@ -17,7 +17,7 @@
                                        item: &Annotatable,
                                        push: &mut dyn FnMut(Annotatable)) {
     let krate = "rustc_serialize";
-    let typaram = &*deriving::hygienic_type_parameter(item, "__D");
+    let typaram = "__D";
 
     let trait_def = TraitDef {
         span,
diff --git a/src/libsyntax_ext/deriving/encodable.rs b/src/libsyntax_ext/deriving/encodable.rs
index 52e74a7..8b18fb2 100644
--- a/src/libsyntax_ext/deriving/encodable.rs
+++ b/src/libsyntax_ext/deriving/encodable.rs
@@ -1,11 +1,12 @@
-//! The compiler code necessary to implement the `#[derive(Encodable)]`
-//! (and `Decodable`, in `decodable.rs`) extension. The idea here is that
-//! type-defining items may be tagged with `#[derive(Encodable, Decodable)]`.
+//! The compiler code necessary to implement the `#[derive(RustcEncodable)]`
+//! (and `RustcDecodable`, in `decodable.rs`) extension. The idea here is that
+//! type-defining items may be tagged with
+//! `#[derive(RustcEncodable, RustcDecodable)]`.
 //!
 //! For example, a type like:
 //!
 //! ```
-//! #[derive(Encodable, Decodable)]
+//! #[derive(RustcEncodable, RustcDecodable)]
 //! struct Node { id: usize }
 //! ```
 //!
@@ -40,15 +41,17 @@
 //! references other non-built-in types. A type definition like:
 //!
 //! ```
-//! # #[derive(Encodable, Decodable)] struct Span;
-//! #[derive(Encodable, Decodable)]
+//! # #[derive(RustcEncodable, RustcDecodable)]
+//! # struct Span;
+//! #[derive(RustcEncodable, RustcDecodable)]
 //! struct Spanned<T> { node: T, span: Span }
 //! ```
 //!
 //! would yield functions like:
 //!
 //! ```
-//! # #[derive(Encodable, Decodable)] struct Span;
+//! # #[derive(RustcEncodable, RustcDecodable)]
+//! # struct Span;
 //! # struct Spanned<T> { node: T, span: Span }
 //! impl<
 //!     S: Encoder<E>,
@@ -82,7 +85,7 @@
 //! }
 //! ```
 
-use crate::deriving::{self, pathvec_std};
+use crate::deriving::pathvec_std;
 use crate::deriving::generic::*;
 use crate::deriving::generic::ty::*;
 
@@ -98,7 +101,7 @@
                                        item: &Annotatable,
                                        push: &mut dyn FnMut(Annotatable)) {
     let krate = "rustc_serialize";
-    let typaram = &*deriving::hygienic_type_parameter(item, "__S");
+    let typaram = "__S";
 
     let trait_def = TraitDef {
         span,
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index d080dc3..1475bac 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -425,7 +425,7 @@
                         return;
                     }
                 };
-                let container_id = cx.current_expansion.id.parent();
+                let container_id = cx.current_expansion.id.expn_data().parent;
                 let is_always_copy =
                     cx.resolver.has_derives(container_id, SpecialDerives::COPY) &&
                     has_no_type_params;
@@ -890,7 +890,7 @@
 
         for (ty, name) in self.args.iter() {
             let ast_ty = ty.to_ty(cx, trait_.span, type_ident, generics);
-            let ident = cx.ident_of(name).gensym();
+            let ident = ast::Ident::from_str_and_span(name, trait_.span);
             arg_tys.push((ident, ast_ty));
 
             let arg_expr = cx.expr_ident(trait_.span, ident);
@@ -928,7 +928,7 @@
 
         let args = {
             let self_args = explicit_self.map(|explicit_self| {
-                let ident = Ident::with_empty_ctxt(kw::SelfLower).with_span_pos(trait_.span);
+                let ident = Ident::with_dummy_span(kw::SelfLower).with_span_pos(trait_.span);
                 ast::Arg::from_self(ThinVec::default(), explicit_self, ident)
             });
             let nonself_args = arg_types.into_iter()
@@ -1210,7 +1210,7 @@
         let vi_idents = self_arg_names.iter()
             .map(|name| {
                 let vi_suffix = format!("{}_vi", &name[..]);
-                cx.ident_of(&vi_suffix[..]).gensym()
+                ast::Ident::from_str_and_span(&vi_suffix[..], trait_.span)
             })
             .collect::<Vec<ast::Ident>>();
 
@@ -1387,7 +1387,10 @@
                 let variant_value =
                     deriving::call_intrinsic(cx, sp, "discriminant_value", vec![self_addr]);
 
-                let target_ty = cx.ty_ident(sp, cx.ident_of(target_type_name));
+                let target_ty = cx.ty_ident(
+                    sp,
+                    ast::Ident::from_str_and_span(target_type_name, sp),
+                );
                 let variant_disr = cx.expr_cast(sp, variant_value, target_ty);
                 let let_stmt = cx.stmt_let(sp, false, ident, variant_disr);
                 index_let_stmts.push(let_stmt);
@@ -1588,7 +1591,7 @@
         let mut ident_exprs = Vec::new();
         for (i, struct_field) in struct_def.fields().iter().enumerate() {
             let sp = struct_field.span.with_ctxt(self.span.ctxt());
-            let ident = cx.ident_of(&format!("{}_{}", prefix, i)).gensym();
+            let ident = ast::Ident::from_str_and_span(&format!("{}_{}", prefix, i), self.span);
             paths.push(ident.with_span_pos(sp));
             let val = cx.expr_path(cx.path_ident(sp, ident));
             let val = if use_temporaries {
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index 399829e..7fcf036 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -72,7 +72,7 @@
                    self_ty: Ident,
                    self_generics: &Generics)
                    -> ast::Path {
-        let mut idents = self.path.iter().map(|s| cx.ident_of(*s)).collect();
+        let mut idents = self.path.iter().map(|s| Ident::from_str_and_span(*s, span)).collect();
         let lt = mk_lifetimes(cx, span, &self.lifetime);
         let tys: Vec<P<ast::Ty>> =
             self.params.iter().map(|t| t.to_ty(cx, span, self_ty, self_generics)).collect();
@@ -209,7 +209,7 @@
             cx.trait_bound(path)
         })
         .collect();
-    cx.typaram(span, cx.ident_of(name), attrs.to_owned(), bounds, None)
+    cx.typaram(span, ast::Ident::from_str_and_span(name, span), attrs.to_owned(), bounds, None)
 }
 
 fn mk_generics(params: Vec<ast::GenericParam>, span: Span) -> Generics {
diff --git a/src/libsyntax_ext/deriving/hash.rs b/src/libsyntax_ext/deriving/hash.rs
index 9787722..2fc594a 100644
--- a/src/libsyntax_ext/deriving/hash.rs
+++ b/src/libsyntax_ext/deriving/hash.rs
@@ -16,7 +16,7 @@
 
     let path = Path::new_(pathvec_std!(cx, hash::Hash), None, vec![], PathKind::Std);
 
-    let typaram = &*deriving::hygienic_type_parameter(item, "__H");
+    let typaram = "__H";
 
     let arg = Path::new_local(typaram);
     let hash_trait_def = TraitDef {
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index 8cd2853..da68eea 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -54,33 +54,6 @@
     }
 }
 
-/// Construct a name for the inner type parameter that can't collide with any type parameters of
-/// the item. This is achieved by starting with a base and then concatenating the names of all
-/// other type parameters.
-// FIXME(aburka): use real hygiene when that becomes possible
-fn hygienic_type_parameter(item: &Annotatable, base: &str) -> String {
-    let mut typaram = String::from(base);
-    if let Annotatable::Item(ref item) = *item {
-        match item.node {
-            ast::ItemKind::Struct(_, ast::Generics { ref params, .. }) |
-            ast::ItemKind::Enum(_, ast::Generics { ref params, .. }) => {
-                for param in params {
-                    match param.kind {
-                        ast::GenericParamKind::Type { .. } => {
-                            typaram.push_str(&param.ident.as_str());
-                        }
-                        _ => {}
-                    }
-                }
-            }
-
-            _ => {}
-        }
-    }
-
-    typaram
-}
-
 /// Constructs an expression that calls an intrinsic
 fn call_intrinsic(cx: &ExtCtxt<'_>,
                   span: Span,
diff --git a/src/libsyntax_ext/env.rs b/src/libsyntax_ext/env.rs
index 442f27c..9834130 100644
--- a/src/libsyntax_ext/env.rs
+++ b/src/libsyntax_ext/env.rs
@@ -23,13 +23,13 @@
     let sp = sp.apply_mark(cx.current_expansion.id);
     let e = match env::var(&*var.as_str()) {
         Err(..) => {
-            let lt = cx.lifetime(sp, Ident::with_empty_ctxt(kw::StaticLifetime));
+            let lt = cx.lifetime(sp, Ident::with_dummy_span(kw::StaticLifetime));
             cx.expr_path(cx.path_all(sp,
                                      true,
                                      cx.std_path(&[sym::option, sym::Option, sym::None]),
                                      vec![GenericArg::Type(cx.ty_rptr(sp,
                                                      cx.ty_ident(sp,
-                                                                 Ident::with_empty_ctxt(sym::str)),
+                                                                 Ident::with_dummy_span(sym::str)),
                                                      Some(lt),
                                                      ast::Mutability::Immutable))],
                                      vec![]))
diff --git a/src/libsyntax_ext/global_allocator.rs b/src/libsyntax_ext/global_allocator.rs
index f788b51..d2121ab 100644
--- a/src/libsyntax_ext/global_allocator.rs
+++ b/src/libsyntax_ext/global_allocator.rs
@@ -29,7 +29,7 @@
     };
 
     // Generate a bunch of new items using the AllocFnFactory
-    let span = item.span.with_ctxt(SyntaxContext::empty().apply_mark(ecx.current_expansion.id));
+    let span = item.span.with_ctxt(SyntaxContext::root().apply_mark(ecx.current_expansion.id));
     let f = AllocFnFactory {
         span,
         kind: AllocatorKind::Global,
@@ -44,7 +44,7 @@
     let const_ty = ecx.ty(span, TyKind::Tup(Vec::new()));
     let const_body = ecx.expr_block(ecx.block(span, stmts));
     let const_item =
-        ecx.item_const(span, Ident::with_empty_ctxt(kw::Underscore), const_ty, const_body);
+        ecx.item_const(span, Ident::with_dummy_span(kw::Underscore), const_ty, const_body);
 
     // Return the original item and the new methods.
     vec![Annotatable::Item(item), Annotatable::Item(const_item)]
@@ -120,7 +120,7 @@
     ) -> P<Expr> {
         match *ty {
             AllocatorTy::Layout => {
-                let usize = self.cx.path_ident(self.span, Ident::with_empty_ctxt(sym::usize));
+                let usize = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::usize));
                 let ty_usize = self.cx.ty_path(usize);
                 let size = ident();
                 let align = ident();
@@ -178,12 +178,12 @@
     }
 
     fn usize(&self) -> P<Ty> {
-        let usize = self.cx.path_ident(self.span, Ident::with_empty_ctxt(sym::usize));
+        let usize = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::usize));
         self.cx.ty_path(usize)
     }
 
     fn ptr_u8(&self) -> P<Ty> {
-        let u8 = self.cx.path_ident(self.span, Ident::with_empty_ctxt(sym::u8));
+        let u8 = self.cx.path_ident(self.span, Ident::with_dummy_span(sym::u8));
         let ty_u8 = self.cx.ty_path(u8);
         self.cx.ty_ptr(self.span, ty_u8, Mutability::Mutable)
     }
diff --git a/src/libsyntax_ext/global_asm.rs b/src/libsyntax_ext/global_asm.rs
index 112192f..73ebeae 100644
--- a/src/libsyntax_ext/global_asm.rs
+++ b/src/libsyntax_ext/global_asm.rs
@@ -30,7 +30,7 @@
                 id: ast::DUMMY_NODE_ID,
                 node: ast::ItemKind::GlobalAsm(P(global_asm)),
                 vis: respan(sp.shrink_to_lo(), ast::VisibilityKind::Inherited),
-                span: sp,
+                span: sp.with_ctxt(cx.backtrace()),
                 tokens: None,
             })])
         }
@@ -61,8 +61,5 @@
         None => return Ok(None),
     };
 
-    Ok(Some(ast::GlobalAsm {
-        asm,
-        ctxt: cx.backtrace(),
-    }))
+    Ok(Some(ast::GlobalAsm { asm }))
 }
diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index 0f3f5c0..4add226 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -42,7 +42,7 @@
 
 pub fn register_builtin_macros(resolver: &mut dyn syntax::ext::base::Resolver, edition: Edition) {
     let mut register = |name, kind| resolver.register_builtin_macro(
-        Ident::with_empty_ctxt(name), SyntaxExtension {
+        Ident::with_dummy_span(name), SyntaxExtension {
             is_builtin: true, ..SyntaxExtension::default(kind, edition)
         },
     );
@@ -57,7 +57,6 @@
     }
 
     register_bang! {
-        __rust_unstable_column: source_util::expand_column,
         asm: asm::expand_asm,
         assert: assert::expand_assert,
         cfg: cfg::expand_cfg,
diff --git a/src/libsyntax_ext/plugin_macro_defs.rs b/src/libsyntax_ext/plugin_macro_defs.rs
index a725f5e..dbfd8fe 100644
--- a/src/libsyntax_ext/plugin_macro_defs.rs
+++ b/src/libsyntax_ext/plugin_macro_defs.rs
@@ -11,7 +11,7 @@
 use syntax::symbol::sym;
 use syntax::tokenstream::*;
 use syntax_pos::{Span, DUMMY_SP};
-use syntax_pos::hygiene::{ExpnId, ExpnInfo, ExpnKind, MacroKind};
+use syntax_pos::hygiene::{ExpnData, ExpnKind, MacroKind};
 
 use std::mem;
 
@@ -43,12 +43,12 @@
 ) {
     if !named_exts.is_empty() {
         let mut extra_items = Vec::new();
-        let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
+        let span = DUMMY_SP.fresh_expansion(ExpnData::allow_unstable(
             ExpnKind::Macro(MacroKind::Attr, sym::plugin), DUMMY_SP, edition,
             [sym::rustc_attrs][..].into(),
         ));
         for (name, ext) in named_exts {
-            resolver.register_builtin_macro(Ident::with_empty_ctxt(name), ext);
+            resolver.register_builtin_macro(Ident::with_dummy_span(name), ext);
             extra_items.push(plugin_macro_def(name, span));
         }
         // The `macro_rules` items must be inserted before any other items.
diff --git a/src/libsyntax_ext/proc_macro_harness.rs b/src/libsyntax_ext/proc_macro_harness.rs
index 7032553..e772eaf 100644
--- a/src/libsyntax_ext/proc_macro_harness.rs
+++ b/src/libsyntax_ext/proc_macro_harness.rs
@@ -3,10 +3,9 @@
 use smallvec::smallvec;
 use syntax::ast::{self, Ident};
 use syntax::attr;
-use syntax::source_map::{ExpnInfo, ExpnKind, respan};
+use syntax::source_map::{ExpnData, ExpnKind, respan};
 use syntax::ext::base::{ExtCtxt, MacroKind};
 use syntax::ext::expand::{AstFragment, ExpansionConfig};
-use syntax::ext::hygiene::ExpnId;
 use syntax::ext::proc_macro::is_proc_macro_attr;
 use syntax::parse::ParseSess;
 use syntax::ptr::P;
@@ -328,7 +327,7 @@
     custom_attrs: &[ProcMacroDef],
     custom_macros: &[ProcMacroDef],
 ) -> P<ast::Item> {
-    let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
+    let span = DUMMY_SP.fresh_expansion(ExpnData::allow_unstable(
         ExpnKind::Macro(MacroKind::Attr, sym::proc_macro), DUMMY_SP, cx.parse_sess.edition,
         [sym::rustc_attrs, sym::proc_macro_internals][..].into(),
     ));
@@ -337,7 +336,7 @@
     let doc = cx.meta_list(span, sym::doc, vec![hidden]);
     let doc_hidden = cx.attribute(doc);
 
-    let proc_macro = Ident::with_empty_ctxt(sym::proc_macro);
+    let proc_macro = Ident::with_dummy_span(sym::proc_macro);
     let krate = cx.item(span,
                         proc_macro,
                         Vec::new(),
@@ -349,7 +348,7 @@
     let custom_derive = Ident::from_str("custom_derive");
     let attr = Ident::from_str("attr");
     let bang = Ident::from_str("bang");
-    let crate_kw = Ident::with_empty_ctxt(kw::Crate);
+    let crate_kw = Ident::with_dummy_span(kw::Crate);
 
     let decls = {
         let local_path = |sp: Span, name| {
diff --git a/src/libsyntax_ext/source_util.rs b/src/libsyntax_ext/source_util.rs
index cbc01b4..e008ed7 100644
--- a/src/libsyntax_ext/source_util.rs
+++ b/src/libsyntax_ext/source_util.rs
@@ -9,8 +9,6 @@
 use smallvec::SmallVec;
 use syntax_pos::{self, Pos, Span};
 
-use std::fs;
-use std::io::ErrorKind;
 use rustc_data_structures::sync::Lrc;
 
 // These macros all relate to the file system; they either return
@@ -114,20 +112,17 @@
         None => return DummyResult::any(sp)
     };
     let file = cx.resolve_path(file, sp);
-    match fs::read_to_string(&file) {
-        Ok(src) => {
-            let interned_src = Symbol::intern(&src);
-
-            // Add this input file to the code map to make it available as
-            // dependency information
-            cx.source_map().new_source_file(file.into(), src);
-
-            base::MacEager::expr(cx.expr_str(sp, interned_src))
+    match cx.source_map().load_binary_file(&file) {
+        Ok(bytes) => match std::str::from_utf8(&bytes) {
+            Ok(src) => {
+                let interned_src = Symbol::intern(&src);
+                base::MacEager::expr(cx.expr_str(sp, interned_src))
+            }
+            Err(_) => {
+                cx.span_err(sp, &format!("{} wasn't a utf-8 file", file.display()));
+                DummyResult::any(sp)
+            }
         },
-        Err(ref e) if e.kind() == ErrorKind::InvalidData => {
-            cx.span_err(sp, &format!("{} wasn't a utf-8 file", file.display()));
-            DummyResult::any(sp)
-        }
         Err(e) => {
             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
             DummyResult::any(sp)
@@ -142,18 +137,8 @@
         None => return DummyResult::any(sp)
     };
     let file = cx.resolve_path(file, sp);
-    match fs::read(&file) {
+    match cx.source_map().load_binary_file(&file) {
         Ok(bytes) => {
-            // Add the contents to the source map if it contains UTF-8.
-            let (contents, bytes) = match String::from_utf8(bytes) {
-                Ok(s) => {
-                    let bytes = s.as_bytes().to_owned();
-                    (s, bytes)
-                },
-                Err(e) => (String::new(), e.into_bytes()),
-            };
-            cx.source_map().new_source_file(file.into(), contents);
-
             base::MacEager::expr(cx.expr_lit(sp, ast::LitKind::ByteStr(Lrc::new(bytes))))
         },
         Err(e) => {
diff --git a/src/libsyntax_ext/standard_library_imports.rs b/src/libsyntax_ext/standard_library_imports.rs
index 68b13bd..8ca3763 100644
--- a/src/libsyntax_ext/standard_library_imports.rs
+++ b/src/libsyntax_ext/standard_library_imports.rs
@@ -1,8 +1,8 @@
 use syntax::{ast, attr};
 use syntax::edition::Edition;
-use syntax::ext::hygiene::{ExpnId, MacroKind};
+use syntax::ext::hygiene::MacroKind;
 use syntax::ptr::P;
-use syntax::source_map::{ExpnInfo, ExpnKind, dummy_spanned, respan};
+use syntax::source_map::{ExpnData, ExpnKind, dummy_spanned, respan};
 use syntax::symbol::{Ident, Symbol, kw, sym};
 use syntax_pos::DUMMY_SP;
 
@@ -32,7 +32,7 @@
         // HACK(eddyb) gensym the injected crates on the Rust 2018 edition,
         // so they don't accidentally interfere with the new import paths.
         let orig_name_sym = Symbol::intern(orig_name_str);
-        let orig_name_ident = Ident::with_empty_ctxt(orig_name_sym);
+        let orig_name_ident = Ident::with_dummy_span(orig_name_sym);
         let (rename, orig_name) = if rust_2018 {
             (orig_name_ident.gensym(), Some(orig_name_sym))
         } else {
@@ -40,7 +40,7 @@
         };
         krate.module.items.insert(0, P(ast::Item {
             attrs: vec![attr::mk_attr_outer(
-                attr::mk_word_item(ast::Ident::with_empty_ctxt(sym::macro_use))
+                attr::mk_word_item(ast::Ident::with_dummy_span(sym::macro_use))
             )],
             vis: dummy_spanned(ast::VisibilityKind::Inherited),
             node: ast::ItemKind::ExternCrate(alt_std_name.or(orig_name)),
@@ -55,7 +55,7 @@
     // the prelude.
     let name = names[0];
 
-    let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
+    let span = DUMMY_SP.fresh_expansion(ExpnData::allow_unstable(
         ExpnKind::Macro(MacroKind::Attr, sym::std_inject), DUMMY_SP, edition,
         [sym::prelude_import][..].into(),
     ));
@@ -66,7 +66,7 @@
         vis: respan(span.shrink_to_lo(), ast::VisibilityKind::Inherited),
         node: ast::ItemKind::Use(P(ast::UseTree {
             prefix: ast::Path {
-                segments: iter::once(ast::Ident::with_empty_ctxt(kw::PathRoot))
+                segments: iter::once(ast::Ident::with_dummy_span(kw::PathRoot))
                     .chain(
                         [name, "prelude", "v1"].iter().cloned()
                             .map(ast::Ident::from_str)
diff --git a/src/libsyntax_ext/test.rs b/src/libsyntax_ext/test.rs
index 993ef25..08582e7 100644
--- a/src/libsyntax_ext/test.rs
+++ b/src/libsyntax_ext/test.rs
@@ -29,7 +29,7 @@
 
     if !ecx.ecfg.should_test { return vec![]; }
 
-    let sp = attr_sp.with_ctxt(SyntaxContext::empty().apply_mark(ecx.current_expansion.id));
+    let sp = attr_sp.with_ctxt(SyntaxContext::root().apply_mark(ecx.current_expansion.id));
     let mut item = anno_item.expect_item();
     item = item.map(|mut item| {
         item.vis = respan(item.vis.span, ast::VisibilityKind::Public);
@@ -93,7 +93,7 @@
         return vec![Annotatable::Item(item)];
     }
 
-    let ctxt = SyntaxContext::empty().apply_mark(cx.current_expansion.id);
+    let ctxt = SyntaxContext::root().apply_mark(cx.current_expansion.id);
     let (sp, attr_sp) = (item.span.with_ctxt(ctxt), attr_sp.with_ctxt(ctxt));
 
     // Gensym "test" so we can extern crate without conflicting with any local names
diff --git a/src/libsyntax_ext/test_harness.rs b/src/libsyntax_ext/test_harness.rs
index 0267637..4a6ea0e 100644
--- a/src/libsyntax_ext/test_harness.rs
+++ b/src/libsyntax_ext/test_harness.rs
@@ -5,14 +5,13 @@
 use syntax::ast::{self, Ident};
 use syntax::attr;
 use syntax::entry::{self, EntryPointType};
-use syntax::ext::base::{ExtCtxt, Resolver};
+use syntax::ext::base::{ExtCtxt, MacroKind, Resolver};
 use syntax::ext::expand::{AstFragment, ExpansionConfig};
-use syntax::ext::hygiene::{ExpnId, MacroKind};
 use syntax::feature_gate::Features;
 use syntax::mut_visit::{*, ExpectOne};
 use syntax::parse::ParseSess;
 use syntax::ptr::P;
-use syntax::source_map::{ExpnInfo, ExpnKind, dummy_spanned};
+use syntax::source_map::{ExpnData, ExpnKind, dummy_spanned};
 use syntax::symbol::{kw, sym, Symbol};
 use syntax_pos::{Span, DUMMY_SP};
 
@@ -150,7 +149,7 @@
             EntryPointType::MainAttr |
             EntryPointType::Start =>
                 item.map(|ast::Item {id, ident, attrs, node, vis, span, tokens}| {
-                    let allow_ident = Ident::with_empty_ctxt(sym::allow);
+                    let allow_ident = Ident::with_dummy_span(sym::allow);
                     let dc_nested = attr::mk_nested_word_item(Ident::from_str("dead_code"));
                     let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
                     let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
@@ -191,7 +190,7 @@
                    tests: Vec<Ident>,
                    tested_submods: Vec<(Ident, Ident)>)
                    -> (P<ast::Item>, Ident) {
-    let super_ = Ident::with_empty_ctxt(kw::Super);
+    let super_ = Ident::with_dummy_span(kw::Super);
 
     let items = tests.into_iter().map(|r| {
         cx.ext_cx.item_use_simple(DUMMY_SP, dummy_spanned(ast::VisibilityKind::Public),
@@ -269,12 +268,12 @@
     //            #![main]
     //            test::test_main_static(&[..tests]);
     //        }
-    let sp = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
+    let sp = DUMMY_SP.fresh_expansion(ExpnData::allow_unstable(
         ExpnKind::Macro(MacroKind::Attr, sym::test_case), DUMMY_SP, cx.ext_cx.parse_sess.edition,
         [sym::main, sym::test, sym::rustc_attrs][..].into(),
     ));
     let ecx = &cx.ext_cx;
-    let test_id = Ident::with_empty_ctxt(sym::test);
+    let test_id = Ident::with_dummy_span(sym::test);
 
     // test::test_main_static(...)
     let mut test_runner = cx.test_runner.clone().unwrap_or(
diff --git a/src/libsyntax_pos/edition.rs b/src/libsyntax_pos/edition.rs
index 2021656..00cd00f 100644
--- a/src/libsyntax_pos/edition.rs
+++ b/src/libsyntax_pos/edition.rs
@@ -1,7 +1,6 @@
 use crate::symbol::{Symbol, sym};
 use std::fmt;
 use std::str::FromStr;
-use crate::GLOBALS;
 
 /// The edition of the compiler (RFC 2052)
 #[derive(Clone, Copy, Hash, PartialEq, PartialOrd, Debug, RustcEncodable, RustcDecodable, Eq)]
@@ -39,10 +38,6 @@
 }
 
 impl Edition {
-    pub fn from_session() -> Edition {
-        GLOBALS.with(|globals| globals.edition)
-    }
-
     pub fn lint_name(&self) -> &'static str {
         match *self {
             Edition::Edition2015 => "rust_2015_compatibility",
diff --git a/src/libsyntax_pos/hygiene.rs b/src/libsyntax_pos/hygiene.rs
index f91a229..ebfb076 100644
--- a/src/libsyntax_pos/hygiene.rs
+++ b/src/libsyntax_pos/hygiene.rs
@@ -13,8 +13,8 @@
 //
 // This explains why `HygieneData`, `SyntaxContext` and `ExpnId` have interfaces
 // with a certain amount of redundancy in them. For example,
-// `SyntaxContext::outer_expn_info` combines `SyntaxContext::outer` and
-// `ExpnId::expn_info` so that two `HygieneData` accesses can be performed within
+// `SyntaxContext::outer_expn_data` combines `SyntaxContext::outer` and
+// `ExpnId::expn_data` so that two `HygieneData` accesses can be performed within
 // a single `HygieneData::with` call.
 //
 // It also explains why many functions appear in `HygieneData` and again in
@@ -56,16 +56,6 @@
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 pub struct ExpnId(u32);
 
-// FIXME: Find a way to merge this with `ExpnInfo`.
-#[derive(Debug)]
-struct InternalExpnData {
-    parent: ExpnId,
-    /// Each expansion should have an associated expansion info, but sometimes there's a delay
-    /// between creation of an expansion ID and obtaining its info (e.g. macros are collected
-    /// first and then resolved later), so we use an `Option` here.
-    expn_info: Option<ExpnInfo>,
-}
-
 /// A property of a macro expansion that determines how identifiers
 /// produced by that expansion are resolved.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug, RustcEncodable, RustcDecodable)]
@@ -86,8 +76,8 @@
 }
 
 impl ExpnId {
-    pub fn fresh(parent: ExpnId, expn_info: Option<ExpnInfo>) -> Self {
-        HygieneData::with(|data| data.fresh_expn(parent, expn_info))
+    pub fn fresh(expn_data: Option<ExpnData>) -> Self {
+        HygieneData::with(|data| data.fresh_expn(expn_data))
     }
 
     /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
@@ -107,21 +97,16 @@
     }
 
     #[inline]
-    pub fn parent(self) -> ExpnId {
-        HygieneData::with(|data| data.parent_expn(self))
+    pub fn expn_data(self) -> ExpnData {
+        HygieneData::with(|data| data.expn_data(self).clone())
     }
 
     #[inline]
-    pub fn expn_info(self) -> Option<ExpnInfo> {
-        HygieneData::with(|data| data.expn_info(self).cloned())
-    }
-
-    #[inline]
-    pub fn set_expn_info(self, info: ExpnInfo) {
+    pub fn set_expn_data(self, expn_data: ExpnData) {
         HygieneData::with(|data| {
-            let old_info = &mut data.expn_data[self.0 as usize].expn_info;
-            assert!(old_info.is_none(), "expansion info is reset for an expansion ID");
-            *old_info = Some(info);
+            let old_expn_data = &mut data.expn_data[self.0 as usize];
+            assert!(old_expn_data.is_none(), "expansion data is reset for an expansion ID");
+            *old_expn_data = Some(expn_data);
         })
     }
 
@@ -139,12 +124,9 @@
     #[inline]
     pub fn looks_like_proc_macro_derive(self) -> bool {
         HygieneData::with(|data| {
-            if data.default_transparency(self) == Transparency::Opaque {
-                if let Some(expn_info) = data.expn_info(self) {
-                    if let ExpnKind::Macro(MacroKind::Derive, _) = expn_info.kind {
-                        return true;
-                    }
-                }
+            let expn_data = data.expn_data(self);
+            if let ExpnKind::Macro(MacroKind::Derive, _) = expn_data.kind {
+                return expn_data.default_transparency == Transparency::Opaque;
             }
             false
         })
@@ -153,7 +135,10 @@
 
 #[derive(Debug)]
 crate struct HygieneData {
-    expn_data: Vec<InternalExpnData>,
+    /// Each expansion should have an associated expansion data, but sometimes there's a delay
+    /// between creation of an expansion ID and obtaining its data (e.g. macros are collected
+    /// first and then resolved later), so we use an `Option` here.
+    expn_data: Vec<Option<ExpnData>>,
     syntax_context_data: Vec<SyntaxContextData>,
     syntax_context_map: FxHashMap<(SyntaxContext, ExpnId, Transparency), SyntaxContext>,
 }
@@ -161,10 +146,7 @@
 impl HygieneData {
     crate fn new(edition: Edition) -> Self {
         HygieneData {
-            expn_data: vec![InternalExpnData {
-                parent: ExpnId::root(),
-                expn_info: Some(ExpnInfo::default(ExpnKind::Root, DUMMY_SP, edition)),
-            }],
+            expn_data: vec![Some(ExpnData::default(ExpnKind::Root, DUMMY_SP, edition))],
             syntax_context_data: vec![SyntaxContextData {
                 outer_expn: ExpnId::root(),
                 outer_transparency: Transparency::Opaque,
@@ -181,25 +163,14 @@
         GLOBALS.with(|globals| f(&mut *globals.hygiene_data.borrow_mut()))
     }
 
-    fn fresh_expn(&mut self, parent: ExpnId, expn_info: Option<ExpnInfo>) -> ExpnId {
-        self.expn_data.push(InternalExpnData { parent, expn_info });
+    fn fresh_expn(&mut self, expn_data: Option<ExpnData>) -> ExpnId {
+        self.expn_data.push(expn_data);
         ExpnId(self.expn_data.len() as u32 - 1)
     }
 
-    fn parent_expn(&self, expn_id: ExpnId) -> ExpnId {
-        self.expn_data[expn_id.0 as usize].parent
-    }
-
-    fn expn_info(&self, expn_id: ExpnId) -> Option<&ExpnInfo> {
-        if expn_id != ExpnId::root() {
-            Some(self.expn_data[expn_id.0 as usize].expn_info.as_ref()
-                     .expect("no expansion info for an expansion ID"))
-        } else {
-            // FIXME: Some code relies on `expn_info().is_none()` meaning "no expansion".
-            // Introduce a method for checking for "no expansion" instead and always return
-            // `ExpnInfo` from this function instead of the `Option`.
-            None
-        }
+    fn expn_data(&self, expn_id: ExpnId) -> &ExpnData {
+        self.expn_data[expn_id.0 as usize].as_ref()
+            .expect("no expansion data for an expansion ID")
     }
 
     fn is_descendant_of(&self, mut expn_id: ExpnId, ancestor: ExpnId) -> bool {
@@ -207,17 +178,11 @@
             if expn_id == ExpnId::root() {
                 return false;
             }
-            expn_id = self.parent_expn(expn_id);
+            expn_id = self.expn_data(expn_id).parent;
         }
         true
     }
 
-    fn default_transparency(&self, expn_id: ExpnId) -> Transparency {
-        self.expn_info(expn_id).map_or(
-            Transparency::SemiTransparent, |einfo| einfo.default_transparency
-        )
-    }
-
     fn modern(&self, ctxt: SyntaxContext) -> SyntaxContext {
         self.syntax_context_data[ctxt.0 as usize].opaque
     }
@@ -246,7 +211,7 @@
 
     fn marks(&self, mut ctxt: SyntaxContext) -> Vec<(ExpnId, Transparency)> {
         let mut marks = Vec::new();
-        while ctxt != SyntaxContext::empty() {
+        while ctxt != SyntaxContext::root() {
             marks.push((self.outer_expn(ctxt), self.outer_transparency(ctxt)));
             ctxt = self.parent_ctxt(ctxt);
         }
@@ -255,12 +220,8 @@
     }
 
     fn walk_chain(&self, mut span: Span, to: SyntaxContext) -> Span {
-        while span.ctxt() != crate::NO_EXPANSION && span.ctxt() != to {
-            if let Some(info) = self.expn_info(self.outer_expn(span.ctxt())) {
-                span = info.call_site;
-            } else {
-                break;
-            }
+        while span.from_expansion() && span.ctxt() != to {
+            span = self.expn_data(self.outer_expn(span.ctxt())).call_site;
         }
         span
     }
@@ -275,7 +236,9 @@
 
     fn apply_mark(&mut self, ctxt: SyntaxContext, expn_id: ExpnId) -> SyntaxContext {
         assert_ne!(expn_id, ExpnId::root());
-        self.apply_mark_with_transparency(ctxt, expn_id, self.default_transparency(expn_id))
+        self.apply_mark_with_transparency(
+            ctxt, expn_id, self.expn_data(expn_id).default_transparency
+        )
     }
 
     fn apply_mark_with_transparency(&mut self, ctxt: SyntaxContext, expn_id: ExpnId,
@@ -285,15 +248,14 @@
             return self.apply_mark_internal(ctxt, expn_id, transparency);
         }
 
-        let call_site_ctxt =
-            self.expn_info(expn_id).map_or(SyntaxContext::empty(), |info| info.call_site.ctxt());
+        let call_site_ctxt = self.expn_data(expn_id).call_site.ctxt();
         let mut call_site_ctxt = if transparency == Transparency::SemiTransparent {
             self.modern(call_site_ctxt)
         } else {
             self.modern_and_legacy(call_site_ctxt)
         };
 
-        if call_site_ctxt == SyntaxContext::empty() {
+        if call_site_ctxt == SyntaxContext::root() {
             return self.apply_mark_internal(ctxt, expn_id, transparency);
         }
 
@@ -400,7 +362,7 @@
 
 impl SyntaxContext {
     #[inline]
-    pub const fn empty() -> Self {
+    pub const fn root() -> Self {
         SyntaxContext(0)
     }
 
@@ -578,20 +540,20 @@
         HygieneData::with(|data| data.outer_expn(self))
     }
 
-    /// `ctxt.outer_expn_info()` is equivalent to but faster than
-    /// `ctxt.outer_expn().expn_info()`.
+    /// `ctxt.outer_expn_data()` is equivalent to but faster than
+    /// `ctxt.outer_expn().expn_data()`.
     #[inline]
-    pub fn outer_expn_info(self) -> Option<ExpnInfo> {
-        HygieneData::with(|data| data.expn_info(data.outer_expn(self)).cloned())
+    pub fn outer_expn_data(self) -> ExpnData {
+        HygieneData::with(|data| data.expn_data(data.outer_expn(self)).clone())
     }
 
-    /// `ctxt.outer_expn_with_info()` is equivalent to but faster than
-    /// `{ let outer = ctxt.outer_expn(); (outer, outer.expn_info()) }`.
+    /// `ctxt.outer_expn_with_data()` is equivalent to but faster than
+    /// `{ let outer = ctxt.outer_expn(); (outer, outer.expn_data()) }`.
     #[inline]
-    pub fn outer_expn_with_info(self) -> (ExpnId, Option<ExpnInfo>) {
+    pub fn outer_expn_with_data(self) -> (ExpnId, ExpnData) {
         HygieneData::with(|data| {
             let outer = data.outer_expn(self);
-            (outer, data.expn_info(outer).cloned())
+            (outer, data.expn_data(outer).clone())
         })
     }
 
@@ -612,10 +574,10 @@
     /// other compiler-generated code to set per-span properties like allowed unstable features.
     /// The returned span belongs to the created expansion and has the new properties,
     /// but its location is inherited from the current span.
-    pub fn fresh_expansion(self, parent: ExpnId, expn_info: ExpnInfo) -> Span {
+    pub fn fresh_expansion(self, expn_data: ExpnData) -> Span {
         HygieneData::with(|data| {
-            let expn_id = data.fresh_expn(parent, Some(expn_info));
-            self.with_ctxt(data.apply_mark(SyntaxContext::empty(), expn_id))
+            let expn_id = data.fresh_expn(Some(expn_data));
+            self.with_ctxt(data.apply_mark(SyntaxContext::root(), expn_id))
         })
     }
 }
@@ -623,8 +585,12 @@
 /// A subset of properties from both macro definition and macro call available through global data.
 /// Avoid using this if you have access to the original definition or call structures.
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
-pub struct ExpnInfo {
+pub struct ExpnData {
     // --- The part unique to each expansion.
+    /// The kind of this expansion - macro or compiler desugaring.
+    pub kind: ExpnKind,
+    /// The expansion that produced this expansion.
+    pub parent: ExpnId,
     /// The location of the actual macro invocation or syntax sugar , e.g.
     /// `let x = foo!();` or `if let Some(y) = x {}`
     ///
@@ -632,18 +598,18 @@
     /// `foo!()` invoked `bar!()` internally, and there was an
     /// expression inside `bar!`; the call_site of the expression in
     /// the expansion would point to the `bar!` invocation; that
-    /// call_site span would have its own ExpnInfo, with the call_site
+    /// call_site span would have its own ExpnData, with the call_site
     /// pointing to the `foo!` invocation.
     pub call_site: Span,
-    /// The kind of this expansion - macro or compiler desugaring.
-    pub kind: ExpnKind,
 
     // --- The part specific to the macro/desugaring definition.
-    // --- FIXME: Share it between expansions with the same definition.
+    // --- It may be reasonable to share this part between expansions with the same definition,
+    // --- but such sharing is known to bring some minor inconveniences without also bringing
+    // --- noticeable perf improvements (PR #62898).
     /// The span of the macro definition (possibly dummy).
     /// This span serves only informational purpose and is not used for resolution.
     pub def_site: Span,
-    /// Transparency used by `apply_mark` for the expansion with this expansion info by default.
+    /// Transparency used by `apply_mark` for the expansion with this expansion data by default.
     pub default_transparency: Transparency,
     /// List of #[unstable]/feature-gated features that the macro is allowed to use
     /// internally without forcing the whole crate to opt-in
@@ -659,12 +625,13 @@
     pub edition: Edition,
 }
 
-impl ExpnInfo {
-    /// Constructs an expansion info with default properties.
-    pub fn default(kind: ExpnKind, call_site: Span, edition: Edition) -> ExpnInfo {
-        ExpnInfo {
-            call_site,
+impl ExpnData {
+    /// Constructs expansion data with default properties.
+    pub fn default(kind: ExpnKind, call_site: Span, edition: Edition) -> ExpnData {
+        ExpnData {
             kind,
+            parent: ExpnId::root(),
+            call_site,
             def_site: DUMMY_SP,
             default_transparency: Transparency::SemiTransparent,
             allow_internal_unstable: None,
@@ -675,12 +642,17 @@
     }
 
     pub fn allow_unstable(kind: ExpnKind, call_site: Span, edition: Edition,
-                          allow_internal_unstable: Lrc<[Symbol]>) -> ExpnInfo {
-        ExpnInfo {
+                          allow_internal_unstable: Lrc<[Symbol]>) -> ExpnData {
+        ExpnData {
             allow_internal_unstable: Some(allow_internal_unstable),
-            ..ExpnInfo::default(kind, call_site, edition)
+            ..ExpnData::default(kind, call_site, edition)
         }
     }
+
+    #[inline]
+    pub fn is_root(&self) -> bool {
+        if let ExpnKind::Root = self.kind { true } else { false }
+    }
 }
 
 /// Expansion kind.
@@ -767,14 +739,14 @@
     }
 }
 
-impl Encodable for SyntaxContext {
+impl Encodable for ExpnId {
     fn encode<E: Encoder>(&self, _: &mut E) -> Result<(), E::Error> {
         Ok(()) // FIXME(jseyfried) intercrate hygiene
     }
 }
 
-impl Decodable for SyntaxContext {
-    fn decode<D: Decoder>(_: &mut D) -> Result<SyntaxContext, D::Error> {
-        Ok(SyntaxContext::empty()) // FIXME(jseyfried) intercrate hygiene
+impl Decodable for ExpnId {
+    fn decode<D: Decoder>(_: &mut D) -> Result<Self, D::Error> {
+        Ok(ExpnId::root()) // FIXME(jseyfried) intercrate hygiene
     }
 }
diff --git a/src/libsyntax_pos/lib.rs b/src/libsyntax_pos/lib.rs
index 02a7433..aa36fe2 100644
--- a/src/libsyntax_pos/lib.rs
+++ b/src/libsyntax_pos/lib.rs
@@ -21,7 +21,7 @@
 pub mod edition;
 use edition::Edition;
 pub mod hygiene;
-pub use hygiene::{ExpnId, SyntaxContext, ExpnInfo, ExpnKind, MacroKind, DesugaringKind};
+pub use hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind, MacroKind, DesugaringKind};
 
 mod span_encoding;
 pub use span_encoding::{Span, DUMMY_SP};
@@ -49,7 +49,6 @@
     symbol_interner: Lock<symbol::Interner>,
     span_interner: Lock<span_encoding::SpanInterner>,
     hygiene_data: Lock<hygiene::HygieneData>,
-    edition: Edition,
 }
 
 impl Globals {
@@ -58,7 +57,6 @@
             symbol_interner: Lock::new(symbol::Interner::fresh()),
             span_interner: Lock::new(span_encoding::SpanInterner::default()),
             hygiene_data: Lock::new(hygiene::HygieneData::new(edition)),
-            edition,
         }
     }
 }
@@ -288,6 +286,17 @@
         span.lo.0 == 0 && span.hi.0 == 0
     }
 
+    /// Returns `true` if this span comes from a macro or desugaring.
+    #[inline]
+    pub fn from_expansion(self) -> bool {
+        self.ctxt() != SyntaxContext::root()
+    }
+
+    #[inline]
+    pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span {
+        Span::new(lo, hi, SyntaxContext::root())
+    }
+
     /// Returns a new span representing an empty span at the beginning of this span
     #[inline]
     pub fn shrink_to_lo(self) -> Span {
@@ -344,20 +353,20 @@
     /// Returns the source span -- this is either the supplied span, or the span for
     /// the macro callsite that expanded to it.
     pub fn source_callsite(self) -> Span {
-        self.ctxt().outer_expn_info().map(|info| info.call_site.source_callsite()).unwrap_or(self)
+        let expn_data = self.ctxt().outer_expn_data();
+        if !expn_data.is_root() { expn_data.call_site.source_callsite() } else { self }
     }
 
     /// The `Span` for the tokens in the previous macro expansion from which `self` was generated,
     /// if any.
     pub fn parent(self) -> Option<Span> {
-        self.ctxt().outer_expn_info().map(|i| i.call_site)
+        let expn_data = self.ctxt().outer_expn_data();
+        if !expn_data.is_root() { Some(expn_data.call_site) } else { None }
     }
 
     /// Edition of the crate from which this span came.
     pub fn edition(self) -> edition::Edition {
-        self.ctxt().outer_expn_info().map_or_else(|| {
-            Edition::from_session()
-        }, |einfo| einfo.edition)
+        self.ctxt().outer_expn_data().edition
     }
 
     #[inline]
@@ -373,52 +382,42 @@
     /// Returns the source callee.
     ///
     /// Returns `None` if the supplied span has no expansion trace,
-    /// else returns the `ExpnInfo` for the macro definition
+    /// else returns the `ExpnData` for the macro definition
     /// corresponding to the source callsite.
-    pub fn source_callee(self) -> Option<ExpnInfo> {
-        fn source_callee(info: ExpnInfo) -> ExpnInfo {
-            match info.call_site.ctxt().outer_expn_info() {
-                Some(info) => source_callee(info),
-                None => info,
-            }
+    pub fn source_callee(self) -> Option<ExpnData> {
+        fn source_callee(expn_data: ExpnData) -> ExpnData {
+            let next_expn_data = expn_data.call_site.ctxt().outer_expn_data();
+            if !next_expn_data.is_root() { source_callee(next_expn_data) } else { expn_data }
         }
-        self.ctxt().outer_expn_info().map(source_callee)
+        let expn_data = self.ctxt().outer_expn_data();
+        if !expn_data.is_root() { Some(source_callee(expn_data)) } else { None }
     }
 
     /// Checks if a span is "internal" to a macro in which `#[unstable]`
     /// items can be used (that is, a macro marked with
     /// `#[allow_internal_unstable]`).
     pub fn allows_unstable(&self, feature: Symbol) -> bool {
-        match self.ctxt().outer_expn_info() {
-            Some(info) => info
-                .allow_internal_unstable
-                .map_or(false, |features| features.iter().any(|&f|
-                    f == feature || f == sym::allow_internal_unstable_backcompat_hack
-                )),
-            None => false,
-        }
+        self.ctxt().outer_expn_data().allow_internal_unstable.map_or(false, |features| {
+            features.iter().any(|&f| {
+                f == feature || f == sym::allow_internal_unstable_backcompat_hack
+            })
+        })
     }
 
     /// Checks if this span arises from a compiler desugaring of kind `kind`.
     pub fn is_desugaring(&self, kind: DesugaringKind) -> bool {
-        match self.ctxt().outer_expn_info() {
-            Some(info) => match info.kind {
-                ExpnKind::Desugaring(k) => k == kind,
-                _ => false,
-            },
-            None => false,
+        match self.ctxt().outer_expn_data().kind {
+            ExpnKind::Desugaring(k) => k == kind,
+            _ => false,
         }
     }
 
     /// Returns the compiler desugaring that created this span, or `None`
     /// if this span is not from a desugaring.
     pub fn desugaring_kind(&self) -> Option<DesugaringKind> {
-        match self.ctxt().outer_expn_info() {
-            Some(info) => match info.kind {
-                ExpnKind::Desugaring(k) => Some(k),
-                _ => None
-            },
-            None => None
+        match self.ctxt().outer_expn_data().kind {
+            ExpnKind::Desugaring(k) => Some(k),
+            _ => None
         }
     }
 
@@ -426,19 +425,20 @@
     /// can be used without triggering the `unsafe_code` lint
     //  (that is, a macro marked with `#[allow_internal_unsafe]`).
     pub fn allows_unsafe(&self) -> bool {
-        match self.ctxt().outer_expn_info() {
-            Some(info) => info.allow_internal_unsafe,
-            None => false,
-        }
+        self.ctxt().outer_expn_data().allow_internal_unsafe
     }
 
     pub fn macro_backtrace(mut self) -> Vec<MacroBacktrace> {
         let mut prev_span = DUMMY_SP;
         let mut result = vec![];
-        while let Some(info) = self.ctxt().outer_expn_info() {
+        loop {
+            let expn_data = self.ctxt().outer_expn_data();
+            if expn_data.is_root() {
+                break;
+            }
             // Don't print recursive invocations.
-            if !info.call_site.source_equal(&prev_span) {
-                let (pre, post) = match info.kind {
+            if !expn_data.call_site.source_equal(&prev_span) {
+                let (pre, post) = match expn_data.kind {
                     ExpnKind::Root => break,
                     ExpnKind::Desugaring(..) => ("desugaring of ", ""),
                     ExpnKind::Macro(macro_kind, _) => match macro_kind {
@@ -448,14 +448,14 @@
                     }
                 };
                 result.push(MacroBacktrace {
-                    call_site: info.call_site,
-                    macro_decl_name: format!("{}{}{}", pre, info.kind.descr(), post),
-                    def_site_span: info.def_site,
+                    call_site: expn_data.call_site,
+                    macro_decl_name: format!("{}{}{}", pre, expn_data.kind.descr(), post),
+                    def_site_span: expn_data.def_site,
                 });
             }
 
             prev_span = self;
-            self = info.call_site;
+            self = expn_data.call_site;
         }
         result
     }
@@ -468,9 +468,9 @@
         // Return the macro span on its own to avoid weird diagnostic output. It is preferable to
         // have an incomplete span than a completely nonsensical one.
         if span_data.ctxt != end_data.ctxt {
-            if span_data.ctxt == SyntaxContext::empty() {
+            if span_data.ctxt == SyntaxContext::root() {
                 return end;
-            } else if end_data.ctxt == SyntaxContext::empty() {
+            } else if end_data.ctxt == SyntaxContext::root() {
                 return self;
             }
             // Both spans fall within a macro.
@@ -479,7 +479,7 @@
         Span::new(
             cmp::min(span_data.lo, end_data.lo),
             cmp::max(span_data.hi, end_data.hi),
-            if span_data.ctxt == SyntaxContext::empty() { end_data.ctxt } else { span_data.ctxt },
+            if span_data.ctxt == SyntaxContext::root() { end_data.ctxt } else { span_data.ctxt },
         )
     }
 
@@ -490,7 +490,7 @@
         Span::new(
             span.hi,
             end.lo,
-            if end.ctxt == SyntaxContext::empty() { end.ctxt } else { span.ctxt },
+            if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt },
         )
     }
 
@@ -501,7 +501,7 @@
         Span::new(
             span.lo,
             end.lo,
-            if end.ctxt == SyntaxContext::empty() { end.ctxt } else { span.ctxt },
+            if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt },
         )
     }
 
@@ -611,7 +611,7 @@
         d.read_struct("Span", 2, |d| {
             let lo = d.read_struct_field("lo", 0, Decodable::decode)?;
             let hi = d.read_struct_field("hi", 1, Decodable::decode)?;
-            Ok(Span::new(lo, hi, NO_EXPANSION))
+            Ok(Span::with_root_ctxt(lo, hi))
         })
     }
 }
@@ -755,8 +755,6 @@
     }
 }
 
-pub const NO_EXPANSION: SyntaxContext = SyntaxContext::empty();
-
 /// Identifies an offset of a multi-byte character in a `SourceFile`.
 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq, Debug)]
 pub struct MultiByteChar {
diff --git a/src/libsyntax_pos/symbol.rs b/src/libsyntax_pos/symbol.rs
index 2d95562..bed898f 100644
--- a/src/libsyntax_pos/symbol.rs
+++ b/src/libsyntax_pos/symbol.rs
@@ -8,13 +8,13 @@
 use rustc_data_structures::newtype_index;
 use rustc_macros::symbols;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
+use rustc_serialize::{UseSpecializedDecodable, UseSpecializedEncodable};
 
 use std::cmp::{PartialEq, Ordering, PartialOrd, Ord};
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::str;
 
-use crate::hygiene::SyntaxContext;
 use crate::{Span, DUMMY_SP, GLOBALS};
 
 #[cfg(test)]
@@ -610,7 +610,6 @@
         rust_eh_personality,
         rust_eh_unwind_resume,
         rust_oom,
-        __rust_unstable_column,
         rvalue_static_promotion,
         sanitizer_runtime,
         _Self,
@@ -745,25 +744,25 @@
         Ident { name, span }
     }
 
-    /// Constructs a new identifier with an empty syntax context.
+    /// Constructs a new identifier with a dummy span.
     #[inline]
-    pub const fn with_empty_ctxt(name: Symbol) -> Ident {
+    pub const fn with_dummy_span(name: Symbol) -> Ident {
         Ident::new(name, DUMMY_SP)
     }
 
     #[inline]
     pub fn invalid() -> Ident {
-        Ident::with_empty_ctxt(kw::Invalid)
+        Ident::with_dummy_span(kw::Invalid)
     }
 
     /// Maps an interned string to an identifier with an empty syntax context.
     pub fn from_interned_str(string: InternedString) -> Ident {
-        Ident::with_empty_ctxt(string.as_symbol())
+        Ident::with_dummy_span(string.as_symbol())
     }
 
     /// Maps a string to an identifier with an empty span.
     pub fn from_str(string: &str) -> Ident {
-        Ident::with_empty_ctxt(Symbol::intern(string))
+        Ident::with_dummy_span(Symbol::intern(string))
     }
 
     /// Maps a string and a span to an identifier.
@@ -849,28 +848,9 @@
     }
 }
 
-impl Encodable for Ident {
-    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
-        if self.span.ctxt().modern() == SyntaxContext::empty() {
-            s.emit_str(&self.as_str())
-        } else { // FIXME(jseyfried): intercrate hygiene
-            let mut string = "#".to_owned();
-            string.push_str(&self.as_str());
-            s.emit_str(&string)
-        }
-    }
-}
+impl UseSpecializedEncodable for Ident {}
 
-impl Decodable for Ident {
-    fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
-        let string = d.read_str()?;
-        Ok(if !string.starts_with('#') {
-            Ident::from_str(&string)
-        } else { // FIXME(jseyfried): intercrate hygiene
-            Ident::from_str(&string[1..]).gensym()
-        })
-    }
-}
+impl UseSpecializedDecodable for Ident {}
 
 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
 /// never equal to any other symbol.
diff --git a/src/libunwind/Cargo.toml b/src/libunwind/Cargo.toml
index f0f1bab..f10df8c 100644
--- a/src/libunwind/Cargo.toml
+++ b/src/libunwind/Cargo.toml
@@ -22,7 +22,7 @@
 cfg-if = "0.1.8"
 
 [build-dependencies]
-cc = { optional = true, version = "1.0.1" }
+cc = { version = "1.0.1" }
 
 [features]
-llvm-libunwind = ["cc"]
+llvm-libunwind = []
diff --git a/src/libunwind/build.rs b/src/libunwind/build.rs
index c1b0dbc..f24d957 100644
--- a/src/libunwind/build.rs
+++ b/src/libunwind/build.rs
@@ -5,14 +5,14 @@
     let target = env::var("TARGET").expect("TARGET was not set");
 
     if cfg!(feature = "llvm-libunwind") &&
-        (target.contains("linux") ||
+        ((target.contains("linux") && !target.contains("musl")) ||
          target.contains("fuchsia")) {
         // Build the unwinding from libunwind C/C++ source code.
-        #[cfg(feature = "llvm-libunwind")]
         llvm_libunwind::compile();
     } else if target.contains("linux") {
         if target.contains("musl") {
-            // musl is handled in lib.rs
+            // linking for musl is handled in lib.rs
+            llvm_libunwind::compile();
         } else if !target.contains("android") {
             println!("cargo:rustc-link-lib=gcc_s");
         }
@@ -23,7 +23,11 @@
     } else if target.contains("netbsd") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("openbsd") {
-        println!("cargo:rustc-link-lib=c++abi");
+        if target.contains("sparc64") {
+            println!("cargo:rustc-link-lib=gcc");
+        } else {
+            println!("cargo:rustc-link-lib=c++abi");
+        }
     } else if target.contains("solaris") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("dragonfly") {
@@ -44,7 +48,6 @@
     }
 }
 
-#[cfg(feature = "llvm-libunwind")]
 mod llvm_libunwind {
     use std::env;
     use std::path::Path;
@@ -96,6 +99,15 @@
             cfg.file(root.join("src").join(src));
         }
 
+        if target_env == "musl" {
+            // use the same C compiler command to compile C++ code so we do not need to setup the
+            // C++ compiler env variables on the builders
+            cfg.cpp(false);
+            // linking for musl is handled in lib.rs
+            cfg.cargo_metadata(false);
+            println!("cargo:rustc-link-search=native={}", env::var("OUT_DIR").unwrap());
+        }
+
         cfg.compile("unwind");
     }
 }
diff --git a/src/test/run-make-fulldeps/reproducible-build-2/Makefile b/src/test/run-make-fulldeps/reproducible-build-2/Makefile
index b96954f..45c9a74 100644
--- a/src/test/run-make-fulldeps/reproducible-build-2/Makefile
+++ b/src/test/run-make-fulldeps/reproducible-build-2/Makefile
@@ -5,7 +5,8 @@
 # Objects are reproducible but their path is not.
 
 all:  \
-	fat_lto
+	fat_lto \
+	sysroot
 
 fat_lto:
 	rm -rf $(TMPDIR) && mkdir $(TMPDIR)
@@ -14,3 +15,12 @@
 	cp $(TMPDIR)/reproducible-build $(TMPDIR)/reproducible-build-a
 	$(RUSTC) reproducible-build.rs -C lto=fat
 	cmp "$(TMPDIR)/reproducible-build-a" "$(TMPDIR)/reproducible-build" || exit 1
+
+sysroot:
+	rm -rf $(TMPDIR) && mkdir $(TMPDIR)
+	$(RUSTC) reproducible-build-aux.rs
+	$(RUSTC) reproducible-build.rs --crate-type rlib --sysroot $(shell $(RUSTC) --print sysroot) --remap-path-prefix=$(shell $(RUSTC) --print sysroot)=/sysroot
+	cp -r $(shell $(RUSTC) --print sysroot) $(TMPDIR)/sysroot
+	cp $(TMPDIR)/libreproducible_build.rlib $(TMPDIR)/libfoo.rlib
+	$(RUSTC) reproducible-build.rs --crate-type rlib --sysroot $(TMPDIR)/sysroot --remap-path-prefix=$(TMPDIR)/sysroot=/sysroot
+	cmp "$(TMPDIR)/libreproducible_build.rlib" "$(TMPDIR)/libfoo.rlib" || exit 1
diff --git a/src/test/ui/.gitattributes b/src/test/ui/.gitattributes
index b62ade7..489dc8a 100644
--- a/src/test/ui/.gitattributes
+++ b/src/test/ui/.gitattributes
@@ -1,2 +1,3 @@
 lexer-crlf-line-endings-string-literal-doc-comment.rs -text
 trailing-carriage-return-in-string.rs -text
+*.bin -text
diff --git a/src/test/ui/abi-sysv64-arg-passing.rs b/src/test/ui/abi/abi-sysv64-arg-passing.rs
similarity index 100%
rename from src/test/ui/abi-sysv64-arg-passing.rs
rename to src/test/ui/abi/abi-sysv64-arg-passing.rs
diff --git a/src/test/ui/abi-sysv64-register-usage.rs b/src/test/ui/abi/abi-sysv64-register-usage.rs
similarity index 100%
rename from src/test/ui/abi-sysv64-register-usage.rs
rename to src/test/ui/abi/abi-sysv64-register-usage.rs
diff --git a/src/test/ui/abort-on-c-abi.rs b/src/test/ui/abi/abort-on-c-abi.rs
similarity index 100%
rename from src/test/ui/abort-on-c-abi.rs
rename to src/test/ui/abi/abort-on-c-abi.rs
diff --git a/src/test/ui/anon-extern-mod.rs b/src/test/ui/abi/anon-extern-mod.rs
similarity index 100%
rename from src/test/ui/anon-extern-mod.rs
rename to src/test/ui/abi/anon-extern-mod.rs
diff --git a/src/test/ui/auxiliary/anon-extern-mod-cross-crate-1.rs b/src/test/ui/abi/auxiliary/anon-extern-mod-cross-crate-1.rs
similarity index 100%
rename from src/test/ui/auxiliary/anon-extern-mod-cross-crate-1.rs
rename to src/test/ui/abi/auxiliary/anon-extern-mod-cross-crate-1.rs
diff --git a/src/test/ui/auxiliary/foreign_lib.rs b/src/test/ui/abi/auxiliary/foreign_lib.rs
similarity index 100%
rename from src/test/ui/auxiliary/foreign_lib.rs
rename to src/test/ui/abi/auxiliary/foreign_lib.rs
diff --git a/src/test/ui/c-stack-as-value.rs b/src/test/ui/abi/c-stack-as-value.rs
similarity index 100%
rename from src/test/ui/c-stack-as-value.rs
rename to src/test/ui/abi/c-stack-as-value.rs
diff --git a/src/test/ui/cabi-int-widening.rs b/src/test/ui/abi/cabi-int-widening.rs
similarity index 100%
rename from src/test/ui/cabi-int-widening.rs
rename to src/test/ui/abi/cabi-int-widening.rs
diff --git a/src/test/ui/consts/auxiliary/anon-extern-mod-cross-crate-1.rs b/src/test/ui/abi/consts/auxiliary/anon-extern-mod-cross-crate-1.rs
similarity index 100%
rename from src/test/ui/consts/auxiliary/anon-extern-mod-cross-crate-1.rs
rename to src/test/ui/abi/consts/auxiliary/anon-extern-mod-cross-crate-1.rs
diff --git a/src/test/ui/cross-crate/anon-extern-mod-cross-crate-2.rs b/src/test/ui/abi/cross-crate/anon-extern-mod-cross-crate-2.rs
similarity index 100%
rename from src/test/ui/cross-crate/anon-extern-mod-cross-crate-2.rs
rename to src/test/ui/abi/cross-crate/anon-extern-mod-cross-crate-2.rs
diff --git a/src/test/ui/cross-crate/auxiliary/anon-extern-mod-cross-crate-1.rs b/src/test/ui/abi/cross-crate/auxiliary/anon-extern-mod-cross-crate-1.rs
similarity index 100%
rename from src/test/ui/cross-crate/auxiliary/anon-extern-mod-cross-crate-1.rs
rename to src/test/ui/abi/cross-crate/auxiliary/anon-extern-mod-cross-crate-1.rs
diff --git a/src/test/ui/duplicated-external-mods.rs b/src/test/ui/abi/duplicated-external-mods.rs
similarity index 100%
rename from src/test/ui/duplicated-external-mods.rs
rename to src/test/ui/abi/duplicated-external-mods.rs
diff --git a/src/test/ui/extern/auxiliary/extern-crosscrate-source.rs b/src/test/ui/abi/extern/auxiliary/extern-crosscrate-source.rs
similarity index 100%
rename from src/test/ui/extern/auxiliary/extern-crosscrate-source.rs
rename to src/test/ui/abi/extern/auxiliary/extern-crosscrate-source.rs
diff --git a/src/test/ui/extern/extern-call-deep.rs b/src/test/ui/abi/extern/extern-call-deep.rs
similarity index 100%
rename from src/test/ui/extern/extern-call-deep.rs
rename to src/test/ui/abi/extern/extern-call-deep.rs
diff --git a/src/test/ui/extern/extern-call-deep2.rs b/src/test/ui/abi/extern/extern-call-deep2.rs
similarity index 100%
rename from src/test/ui/extern/extern-call-deep2.rs
rename to src/test/ui/abi/extern/extern-call-deep2.rs
diff --git a/src/test/ui/extern/extern-call-direct.rs b/src/test/ui/abi/extern/extern-call-direct.rs
similarity index 100%
rename from src/test/ui/extern/extern-call-direct.rs
rename to src/test/ui/abi/extern/extern-call-direct.rs
diff --git a/src/test/ui/extern/extern-call-indirect.rs b/src/test/ui/abi/extern/extern-call-indirect.rs
similarity index 100%
rename from src/test/ui/extern/extern-call-indirect.rs
rename to src/test/ui/abi/extern/extern-call-indirect.rs
diff --git a/src/test/ui/extern/extern-call-scrub.rs b/src/test/ui/abi/extern/extern-call-scrub.rs
similarity index 100%
rename from src/test/ui/extern/extern-call-scrub.rs
rename to src/test/ui/abi/extern/extern-call-scrub.rs
diff --git a/src/test/ui/extern/extern-crosscrate.rs b/src/test/ui/abi/extern/extern-crosscrate.rs
similarity index 100%
rename from src/test/ui/extern/extern-crosscrate.rs
rename to src/test/ui/abi/extern/extern-crosscrate.rs
diff --git a/src/test/ui/extern/extern-pass-TwoU16s.rs b/src/test/ui/abi/extern/extern-pass-TwoU16s.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-TwoU16s.rs
rename to src/test/ui/abi/extern/extern-pass-TwoU16s.rs
diff --git a/src/test/ui/extern/extern-pass-TwoU32s.rs b/src/test/ui/abi/extern/extern-pass-TwoU32s.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-TwoU32s.rs
rename to src/test/ui/abi/extern/extern-pass-TwoU32s.rs
diff --git a/src/test/ui/extern/extern-pass-TwoU64s.rs b/src/test/ui/abi/extern/extern-pass-TwoU64s.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-TwoU64s.rs
rename to src/test/ui/abi/extern/extern-pass-TwoU64s.rs
diff --git a/src/test/ui/extern/extern-pass-TwoU8s.rs b/src/test/ui/abi/extern/extern-pass-TwoU8s.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-TwoU8s.rs
rename to src/test/ui/abi/extern/extern-pass-TwoU8s.rs
diff --git a/src/test/ui/extern/extern-pass-char.rs b/src/test/ui/abi/extern/extern-pass-char.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-char.rs
rename to src/test/ui/abi/extern/extern-pass-char.rs
diff --git a/src/test/ui/extern/extern-pass-double.rs b/src/test/ui/abi/extern/extern-pass-double.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-double.rs
rename to src/test/ui/abi/extern/extern-pass-double.rs
diff --git a/src/test/ui/extern/extern-pass-empty.rs b/src/test/ui/abi/extern/extern-pass-empty.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-empty.rs
rename to src/test/ui/abi/extern/extern-pass-empty.rs
diff --git a/src/test/ui/extern/extern-pass-u32.rs b/src/test/ui/abi/extern/extern-pass-u32.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-u32.rs
rename to src/test/ui/abi/extern/extern-pass-u32.rs
diff --git a/src/test/ui/extern/extern-pass-u64.rs b/src/test/ui/abi/extern/extern-pass-u64.rs
similarity index 100%
rename from src/test/ui/extern/extern-pass-u64.rs
rename to src/test/ui/abi/extern/extern-pass-u64.rs
diff --git a/src/test/ui/extern/extern-return-TwoU16s.rs b/src/test/ui/abi/extern/extern-return-TwoU16s.rs
similarity index 100%
rename from src/test/ui/extern/extern-return-TwoU16s.rs
rename to src/test/ui/abi/extern/extern-return-TwoU16s.rs
diff --git a/src/test/ui/extern/extern-return-TwoU32s.rs b/src/test/ui/abi/extern/extern-return-TwoU32s.rs
similarity index 100%
rename from src/test/ui/extern/extern-return-TwoU32s.rs
rename to src/test/ui/abi/extern/extern-return-TwoU32s.rs
diff --git a/src/test/ui/extern/extern-return-TwoU64s.rs b/src/test/ui/abi/extern/extern-return-TwoU64s.rs
similarity index 100%
rename from src/test/ui/extern/extern-return-TwoU64s.rs
rename to src/test/ui/abi/extern/extern-return-TwoU64s.rs
diff --git a/src/test/ui/extern/extern-return-TwoU8s.rs b/src/test/ui/abi/extern/extern-return-TwoU8s.rs
similarity index 100%
rename from src/test/ui/extern/extern-return-TwoU8s.rs
rename to src/test/ui/abi/extern/extern-return-TwoU8s.rs
diff --git a/src/test/ui/foreign/auxiliary/foreign_lib.rs b/src/test/ui/abi/foreign/auxiliary/foreign_lib.rs
similarity index 100%
rename from src/test/ui/foreign/auxiliary/foreign_lib.rs
rename to src/test/ui/abi/foreign/auxiliary/foreign_lib.rs
diff --git a/src/test/ui/foreign/foreign-call-no-runtime.rs b/src/test/ui/abi/foreign/foreign-call-no-runtime.rs
similarity index 100%
rename from src/test/ui/foreign/foreign-call-no-runtime.rs
rename to src/test/ui/abi/foreign/foreign-call-no-runtime.rs
diff --git a/src/test/ui/foreign/foreign-dupe.rs b/src/test/ui/abi/foreign/foreign-dupe.rs
similarity index 100%
rename from src/test/ui/foreign/foreign-dupe.rs
rename to src/test/ui/abi/foreign/foreign-dupe.rs
diff --git a/src/test/ui/foreign/foreign-fn-with-byval.rs b/src/test/ui/abi/foreign/foreign-fn-with-byval.rs
similarity index 100%
rename from src/test/ui/foreign/foreign-fn-with-byval.rs
rename to src/test/ui/abi/foreign/foreign-fn-with-byval.rs
diff --git a/src/test/ui/foreign/foreign-no-abi.rs b/src/test/ui/abi/foreign/foreign-no-abi.rs
similarity index 100%
rename from src/test/ui/foreign/foreign-no-abi.rs
rename to src/test/ui/abi/foreign/foreign-no-abi.rs
diff --git a/src/test/ui/invoke-external-foreign.rs b/src/test/ui/abi/invoke-external-foreign.rs
similarity index 100%
rename from src/test/ui/invoke-external-foreign.rs
rename to src/test/ui/abi/invoke-external-foreign.rs
diff --git a/src/test/ui/lib-defaults.rs b/src/test/ui/abi/lib-defaults.rs
similarity index 100%
rename from src/test/ui/lib-defaults.rs
rename to src/test/ui/abi/lib-defaults.rs
diff --git a/src/test/ui/macros/macros-in-extern.rs b/src/test/ui/abi/macros/macros-in-extern.rs
similarity index 100%
rename from src/test/ui/macros/macros-in-extern.rs
rename to src/test/ui/abi/macros/macros-in-extern.rs
diff --git a/src/test/ui/macros/macros-in-extern.stderr b/src/test/ui/abi/macros/macros-in-extern.stderr
similarity index 100%
rename from src/test/ui/macros/macros-in-extern.stderr
rename to src/test/ui/abi/macros/macros-in-extern.stderr
diff --git a/src/test/ui/mir/mir_codegen_calls_variadic.rs b/src/test/ui/abi/mir/mir_codegen_calls_variadic.rs
similarity index 100%
rename from src/test/ui/mir/mir_codegen_calls_variadic.rs
rename to src/test/ui/abi/mir/mir_codegen_calls_variadic.rs
diff --git a/src/test/ui/numbers-arithmetic/i128-ffi.rs b/src/test/ui/abi/numbers-arithmetic/i128-ffi.rs
similarity index 100%
rename from src/test/ui/numbers-arithmetic/i128-ffi.rs
rename to src/test/ui/abi/numbers-arithmetic/i128-ffi.rs
diff --git a/src/test/ui/abi/proc-macro/auxiliary/test-macros.rs b/src/test/ui/abi/proc-macro/auxiliary/test-macros.rs
new file mode 100644
index 0000000..27efa44
--- /dev/null
+++ b/src/test/ui/abi/proc-macro/auxiliary/test-macros.rs
@@ -0,0 +1,112 @@
+// force-host
+// no-prefer-dynamic
+
+// Proc macros commonly used by tests.
+// `panic`/`print` -> `panic_bang`/`print_bang` to avoid conflicts with standard macros.
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+use proc_macro::TokenStream;
+
+// Macro that return empty token stream.
+
+#[proc_macro]
+pub fn empty(_: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+#[proc_macro_attribute]
+pub fn empty_attr(_: TokenStream, _: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+#[proc_macro_derive(Empty, attributes(empty_helper))]
+pub fn empty_derive(_: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+// Macro that panics.
+
+#[proc_macro]
+pub fn panic_bang(_: TokenStream) -> TokenStream {
+    panic!("panic-bang");
+}
+
+#[proc_macro_attribute]
+pub fn panic_attr(_: TokenStream, _: TokenStream) -> TokenStream {
+    panic!("panic-attr");
+}
+
+#[proc_macro_derive(Panic, attributes(panic_helper))]
+pub fn panic_derive(_: TokenStream) -> TokenStream {
+    panic!("panic-derive");
+}
+
+// Macros that return the input stream.
+
+#[proc_macro]
+pub fn identity(input: TokenStream) -> TokenStream {
+    input
+}
+
+#[proc_macro_attribute]
+pub fn identity_attr(_: TokenStream, input: TokenStream) -> TokenStream {
+    input
+}
+
+#[proc_macro_derive(Identity, attributes(identity_helper))]
+pub fn identity_derive(input: TokenStream) -> TokenStream {
+    input
+}
+
+// Macros that iterate and re-collect the input stream.
+
+#[proc_macro]
+pub fn recollect(input: TokenStream) -> TokenStream {
+    input.into_iter().collect()
+}
+
+#[proc_macro_attribute]
+pub fn recollect_attr(_: TokenStream, input: TokenStream) -> TokenStream {
+    input.into_iter().collect()
+}
+
+#[proc_macro_derive(Recollect, attributes(recollect_helper))]
+pub fn recollect_derive(input: TokenStream) -> TokenStream {
+    input.into_iter().collect()
+}
+
+// Macros that print their input in the original and re-collected forms (if they differ).
+
+fn print_helper(input: TokenStream, kind: &str) -> TokenStream {
+    let input_display = format!("{}", input);
+    let input_debug = format!("{:#?}", input);
+    let recollected = input.into_iter().collect();
+    let recollected_display = format!("{}", recollected);
+    let recollected_debug = format!("{:#?}", recollected);
+    println!("PRINT-{} INPUT (DISPLAY): {}", kind, input_display);
+    if recollected_display != input_display {
+        println!("PRINT-{} RE-COLLECTED (DISPLAY): {}", kind, recollected_display);
+    }
+    println!("PRINT-{} INPUT (DEBUG): {}", kind, input_debug);
+    if recollected_debug != input_debug {
+        println!("PRINT-{} RE-COLLECTED (DEBUG): {}", kind, recollected_debug);
+    }
+    recollected
+}
+
+#[proc_macro]
+pub fn print_bang(input: TokenStream) -> TokenStream {
+    print_helper(input, "BANG")
+}
+
+#[proc_macro_attribute]
+pub fn print_attr(_: TokenStream, input: TokenStream) -> TokenStream {
+    print_helper(input, "ATTR")
+}
+
+#[proc_macro_derive(Print, attributes(print_helper))]
+pub fn print_derive(input: TokenStream) -> TokenStream {
+    print_helper(input, "DERIVE")
+}
diff --git a/src/test/ui/proc-macro/macros-in-extern.rs b/src/test/ui/abi/proc-macro/macros-in-extern.rs
similarity index 100%
rename from src/test/ui/proc-macro/macros-in-extern.rs
rename to src/test/ui/abi/proc-macro/macros-in-extern.rs
diff --git a/src/test/ui/proc-macro/macros-in-extern.stderr b/src/test/ui/abi/proc-macro/macros-in-extern.stderr
similarity index 100%
rename from src/test/ui/proc-macro/macros-in-extern.stderr
rename to src/test/ui/abi/proc-macro/macros-in-extern.stderr
diff --git a/src/test/ui/segfault-no-out-of-stack.rs b/src/test/ui/abi/segfault-no-out-of-stack.rs
similarity index 100%
rename from src/test/ui/segfault-no-out-of-stack.rs
rename to src/test/ui/abi/segfault-no-out-of-stack.rs
diff --git a/src/test/ui/stack-probes-lto.rs b/src/test/ui/abi/stack-probes-lto.rs
similarity index 100%
rename from src/test/ui/stack-probes-lto.rs
rename to src/test/ui/abi/stack-probes-lto.rs
diff --git a/src/test/ui/stack-probes.rs b/src/test/ui/abi/stack-probes.rs
similarity index 100%
rename from src/test/ui/stack-probes.rs
rename to src/test/ui/abi/stack-probes.rs
diff --git a/src/test/ui/statics/static-mut-foreign.rs b/src/test/ui/abi/statics/static-mut-foreign.rs
similarity index 100%
rename from src/test/ui/statics/static-mut-foreign.rs
rename to src/test/ui/abi/statics/static-mut-foreign.rs
diff --git a/src/test/ui/structs-enums/struct-return.rs b/src/test/ui/abi/struct-enums/struct-return.rs
similarity index 100%
rename from src/test/ui/structs-enums/struct-return.rs
rename to src/test/ui/abi/struct-enums/struct-return.rs
diff --git a/src/test/ui/union/union-c-interop.rs b/src/test/ui/abi/union/union-c-interop.rs
similarity index 100%
rename from src/test/ui/union/union-c-interop.rs
rename to src/test/ui/abi/union/union-c-interop.rs
diff --git a/src/test/ui/variadic-ffi.rs b/src/test/ui/abi/variadic-ffi.rs
similarity index 100%
rename from src/test/ui/variadic-ffi.rs
rename to src/test/ui/abi/variadic-ffi.rs
diff --git a/src/test/ui/async-await/issues/issue-63388-1.nll.stderr b/src/test/ui/async-await/issues/issue-63388-1.nll.stderr
index fab5892..64fd1a4 100644
--- a/src/test/ui/async-await/issues/issue-63388-1.nll.stderr
+++ b/src/test/ui/async-await/issues/issue-63388-1.nll.stderr
@@ -4,7 +4,7 @@
 LL |     ) -> &dyn Foo
    |          ^^^^^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#27r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#22r
 
 error: lifetime may not live long enough
   --> $DIR/issue-63388-1.rs:15:5
diff --git a/src/test/ui/async-await/suggest-switching-edition-on-await.rs b/src/test/ui/async-await/suggest-switching-edition-on-await.rs
new file mode 100644
index 0000000..1402f1c
--- /dev/null
+++ b/src/test/ui/async-await/suggest-switching-edition-on-await.rs
@@ -0,0 +1,45 @@
+use std::pin::Pin;
+use std::future::Future;
+
+fn main() {}
+
+fn await_on_struct_missing() {
+    struct S;
+    let x = S;
+    x.await;
+    //~^ ERROR no field `await` on type
+    //~| NOTE unknown field
+    //~| NOTE to `.await` a `Future`, switch to Rust 2018
+    //~| HELP set `edition = "2018"` in `Cargo.toml`
+    //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide
+}
+
+fn await_on_struct_similar() {
+    struct S {
+        awai: u8,
+    }
+    let x = S { awai: 42 };
+    x.await;
+    //~^ ERROR no field `await` on type
+    //~| HELP a field with a similar name exists
+    //~| NOTE to `.await` a `Future`, switch to Rust 2018
+    //~| HELP set `edition = "2018"` in `Cargo.toml`
+    //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide
+}
+
+fn await_on_63533(x: Pin<&mut dyn Future<Output = ()>>) {
+    x.await;
+    //~^ ERROR no field `await` on type
+    //~| NOTE unknown field
+    //~| NOTE to `.await` a `Future`, switch to Rust 2018
+    //~| HELP set `edition = "2018"` in `Cargo.toml`
+    //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide
+}
+
+fn await_on_apit(x: impl Future<Output = ()>) {
+    x.await;
+    //~^ ERROR no field `await` on type
+    //~| NOTE to `.await` a `Future`, switch to Rust 2018
+    //~| HELP set `edition = "2018"` in `Cargo.toml`
+    //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide
+}
diff --git a/src/test/ui/async-await/suggest-switching-edition-on-await.stderr b/src/test/ui/async-await/suggest-switching-edition-on-await.stderr
new file mode 100644
index 0000000..f623511
--- /dev/null
+++ b/src/test/ui/async-await/suggest-switching-edition-on-await.stderr
@@ -0,0 +1,43 @@
+error[E0609]: no field `await` on type `await_on_struct_missing::S`
+  --> $DIR/suggest-switching-edition-on-await.rs:9:7
+   |
+LL |     x.await;
+   |       ^^^^^ unknown field
+   |
+   = note: to `.await` a `Future`, switch to Rust 2018
+   = help: set `edition = "2018"` in `Cargo.toml`
+   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
+
+error[E0609]: no field `await` on type `await_on_struct_similar::S`
+  --> $DIR/suggest-switching-edition-on-await.rs:22:7
+   |
+LL |     x.await;
+   |       ^^^^^ help: a field with a similar name exists: `awai`
+   |
+   = note: to `.await` a `Future`, switch to Rust 2018
+   = help: set `edition = "2018"` in `Cargo.toml`
+   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
+
+error[E0609]: no field `await` on type `std::pin::Pin<&mut dyn std::future::Future<Output = ()>>`
+  --> $DIR/suggest-switching-edition-on-await.rs:31:7
+   |
+LL |     x.await;
+   |       ^^^^^ unknown field
+   |
+   = note: to `.await` a `Future`, switch to Rust 2018
+   = help: set `edition = "2018"` in `Cargo.toml`
+   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
+
+error[E0609]: no field `await` on type `impl Future<Output = ()>`
+  --> $DIR/suggest-switching-edition-on-await.rs:40:7
+   |
+LL |     x.await;
+   |       ^^^^^
+   |
+   = note: to `.await` a `Future`, switch to Rust 2018
+   = help: set `edition = "2018"` in `Cargo.toml`
+   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0609`.
diff --git a/src/test/ui/derives/derive-hygiene.rs b/src/test/ui/derives/derive-hygiene.rs
new file mode 100644
index 0000000..4fa83c4
--- /dev/null
+++ b/src/test/ui/derives/derive-hygiene.rs
@@ -0,0 +1,121 @@
+// Make sure that built-in derives don't rely on the user not declaring certain
+// names to work properly.
+
+// check-pass
+
+#![allow(nonstandard_style)]
+#![feature(decl_macro)]
+
+use std::prelude::v1::test as inline;
+
+static f: () = ();
+static cmp: () = ();
+static other: () = ();
+static state: () = ();
+static __self_0_0: () = ();
+static __self_1_0: () = ();
+static __self_vi: () = ();
+static __arg_1_0: () = ();
+static debug_trait_builder: () = ();
+
+struct isize;
+trait i16 {}
+
+trait MethodsInDerives: Sized {
+    fn debug_tuple(self) {}
+    fn debug_struct(self) {}
+    fn field(self) {}
+    fn finish(self) {}
+    fn clone(self) {}
+    fn cmp(self) {}
+    fn partial_cmp(self) {}
+    fn eq(self) {}
+    fn ne(self) {}
+    fn le(self) {}
+    fn lt(self) {}
+    fn ge(self) {}
+    fn gt(self) {}
+    fn hash(self) {}
+}
+
+trait GenericAny<T, U> {}
+impl<S, T, U> GenericAny<T, U> for S {}
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+enum __H { V(i32), }
+
+#[repr(i16)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+enum W { A, B }
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+struct X<A: GenericAny<A, self::X<i32>>> {
+    A: A,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+struct Y<B>(B)
+where
+    B: From<B>;
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+enum Z<C> {
+    C(C),
+    B { C: C },
+}
+
+// Make sure that we aren't using `self::` in paths, since it doesn't work in
+// non-module scopes.
+const NON_MODULE: () = {
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum __H { V(i32), }
+
+    #[repr(i16)]
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum W { A, B }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+    struct X<A: Fn(A) -> self::X<i32>> {
+        A: A,
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+    struct Y<B>(B)
+    where
+        B: From<B>;
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum Z<C> {
+        C(C),
+        B { C: C },
+    }
+};
+
+macro m() {
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum __H { V(i32), }
+
+    #[repr(i16)]
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum W { A, B }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+    struct X<A: GenericAny<A, self::X<i32>>> {
+        A: A,
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Default, Hash)]
+    struct Y<B>(B)
+    where
+        B: From<B>;
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+    enum Z<C> {
+        C(C),
+        B { C: C },
+    }
+}
+
+m!();
+
+fn main() {}
diff --git a/src/test/ui/dropck/dropck_trait_cycle_checked.stderr b/src/test/ui/dropck/dropck_trait_cycle_checked.stderr
index 1e77920..dc3fbed 100644
--- a/src/test/ui/dropck/dropck_trait_cycle_checked.stderr
+++ b/src/test/ui/dropck/dropck_trait_cycle_checked.stderr
@@ -2,7 +2,7 @@
   --> $DIR/dropck_trait_cycle_checked.rs:111:13
    |
 LL |     let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
-   |                                                                               -------- cast requires that `o2` is borrowed for `'static`
+   |                                                                     -------- cast requires that `o2` is borrowed for `'static`
 LL |     o1.set0(&o2);
    |             ^^^ borrowed value does not live long enough
 ...
@@ -13,7 +13,7 @@
   --> $DIR/dropck_trait_cycle_checked.rs:112:13
    |
 LL |     let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
-   |                                                                                         -------- cast requires that `o3` is borrowed for `'static`
+   |                                                                     -------- cast requires that `o3` is borrowed for `'static`
 LL |     o1.set0(&o2);
 LL |     o1.set1(&o3);
    |             ^^^ borrowed value does not live long enough
@@ -37,7 +37,7 @@
   --> $DIR/dropck_trait_cycle_checked.rs:114:13
    |
 LL |     let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
-   |                                                                                         -------- cast requires that `o3` is borrowed for `'static`
+   |                                                                               -------- cast requires that `o3` is borrowed for `'static`
 ...
 LL |     o2.set1(&o3);
    |             ^^^ borrowed value does not live long enough
@@ -49,7 +49,7 @@
   --> $DIR/dropck_trait_cycle_checked.rs:115:13
    |
 LL |     let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
-   |                                                                     -------- cast requires that `o1` is borrowed for `'static`
+   |                                                                                         -------- cast requires that `o1` is borrowed for `'static`
 ...
 LL |     o3.set0(&o1);
    |             ^^^ borrowed value does not live long enough
@@ -61,7 +61,7 @@
   --> $DIR/dropck_trait_cycle_checked.rs:116:13
    |
 LL |     let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
-   |                                                                               -------- cast requires that `o2` is borrowed for `'static`
+   |                                                                                         -------- cast requires that `o2` is borrowed for `'static`
 ...
 LL |     o3.set1(&o2);
    |             ^^^ borrowed value does not live long enough
diff --git a/src/test/ui/duplicate/duplicate-type-parameter.stderr b/src/test/ui/duplicate/duplicate-type-parameter.stderr
index 8606479..6754574 100644
--- a/src/test/ui/duplicate/duplicate-type-parameter.stderr
+++ b/src/test/ui/duplicate/duplicate-type-parameter.stderr
@@ -1,4 +1,4 @@
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:1:12
    |
 LL | type Foo<T,T> = Option<T>;
@@ -6,7 +6,7 @@
    |          |
    |          first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:4:14
    |
 LL | struct Bar<T,T>(T);
@@ -14,7 +14,7 @@
    |            |
    |            first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:7:14
    |
 LL | struct Baz<T,T> {
@@ -22,7 +22,7 @@
    |            |
    |            first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:12:12
    |
 LL | enum Boo<T,T> {
@@ -30,7 +30,7 @@
    |          |
    |          first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:18:11
    |
 LL | fn quux<T,T>(x: T) {}
@@ -38,7 +38,7 @@
    |         |
    |         first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:21:13
    |
 LL | trait Qux<T,T> {}
@@ -46,7 +46,7 @@
    |           |
    |           first use of `T`
 
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/duplicate-type-parameter.rs:24:8
    |
 LL | impl<T,T> Qux<T,T> for Option<T> {}
diff --git a/src/test/ui/error-codes/E0194.rs b/src/test/ui/error-codes/E0194.rs
index 71eff0e..8a43f38 100644
--- a/src/test/ui/error-codes/E0194.rs
+++ b/src/test/ui/error-codes/E0194.rs
@@ -1,7 +1,7 @@
 trait Foo<T> {
     fn do_something(&self) -> T;
     fn do_something_else<T: Clone>(&self, bar: T);
-    //~^ ERROR E0194
+    //~^ ERROR E0403
 }
 
 fn main() {
diff --git a/src/test/ui/error-codes/E0194.stderr b/src/test/ui/error-codes/E0194.stderr
index ab4918a..f2c908e 100644
--- a/src/test/ui/error-codes/E0194.stderr
+++ b/src/test/ui/error-codes/E0194.stderr
@@ -1,12 +1,12 @@
-error[E0194]: type parameter `T` shadows another type parameter of the same name
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/E0194.rs:3:26
    |
 LL | trait Foo<T> {
-   |           - first `T` declared here
+   |           - first use of `T`
 LL |     fn do_something(&self) -> T;
 LL |     fn do_something_else<T: Clone>(&self, bar: T);
-   |                          ^ shadows another type parameter
+   |                          ^ already used
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0194`.
+For more information about this error, try `rustc --explain E0403`.
diff --git a/src/test/ui/error-codes/E0403.stderr b/src/test/ui/error-codes/E0403.stderr
index 2bd7de6..d76a58a 100644
--- a/src/test/ui/error-codes/E0403.stderr
+++ b/src/test/ui/error-codes/E0403.stderr
@@ -1,4 +1,4 @@
-error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/E0403.rs:1:11
    |
 LL | fn foo<T, T>(s: T, u: T) {}
diff --git a/src/test/ui/feature-gates/feature-gate-generators.rs b/src/test/ui/feature-gates/feature-gate-generators.rs
index cee930f..382d891 100644
--- a/src/test/ui/feature-gates/feature-gate-generators.rs
+++ b/src/test/ui/feature-gates/feature-gate-generators.rs
@@ -2,3 +2,9 @@
     yield true; //~ ERROR yield syntax is experimental
                 //~^ ERROR yield statement outside of generator literal
 }
+
+#[cfg(FALSE)]
+fn foo() {
+    yield; //~ ERROR yield syntax is experimental
+    yield 0; //~ ERROR yield syntax is experimental
+}
diff --git a/src/test/ui/feature-gates/feature-gate-generators.stderr b/src/test/ui/feature-gates/feature-gate-generators.stderr
index cdb0560..24b814b 100644
--- a/src/test/ui/feature-gates/feature-gate-generators.stderr
+++ b/src/test/ui/feature-gates/feature-gate-generators.stderr
@@ -7,12 +7,30 @@
    = note: for more information, see https://github.com/rust-lang/rust/issues/43122
    = help: add `#![feature(generators)]` to the crate attributes to enable
 
+error[E0658]: yield syntax is experimental
+  --> $DIR/feature-gate-generators.rs:8:5
+   |
+LL |     yield;
+   |     ^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/43122
+   = help: add `#![feature(generators)]` to the crate attributes to enable
+
+error[E0658]: yield syntax is experimental
+  --> $DIR/feature-gate-generators.rs:9:5
+   |
+LL |     yield 0;
+   |     ^^^^^^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/43122
+   = help: add `#![feature(generators)]` to the crate attributes to enable
+
 error[E0627]: yield statement outside of generator literal
   --> $DIR/feature-gate-generators.rs:2:5
    |
 LL |     yield true;
    |     ^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-rustc-diagnostic-macros.stderr b/src/test/ui/feature-gates/feature-gate-rustc-diagnostic-macros.stderr
index 478bc09..676b8b9 100644
--- a/src/test/ui/feature-gates/feature-gate-rustc-diagnostic-macros.stderr
+++ b/src/test/ui/feature-gates/feature-gate-rustc-diagnostic-macros.stderr
@@ -4,17 +4,17 @@
 LL | __build_diagnostic_array!(DIAGNOSTICS);
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: cannot find macro `__register_diagnostic!` in this scope
-  --> $DIR/feature-gate-rustc-diagnostic-macros.rs:4:1
-   |
-LL | __register_diagnostic!(E0001);
-   | ^^^^^^^^^^^^^^^^^^^^^
-
 error: cannot find macro `__diagnostic_used!` in this scope
   --> $DIR/feature-gate-rustc-diagnostic-macros.rs:8:5
    |
 LL |     __diagnostic_used!(E0001);
    |     ^^^^^^^^^^^^^^^^^
 
+error: cannot find macro `__register_diagnostic!` in this scope
+  --> $DIR/feature-gate-rustc-diagnostic-macros.rs:4:1
+   |
+LL | __register_diagnostic!(E0001);
+   | ^^^^^^^^^^^^^^^^^^^^^
+
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/hygiene/auxiliary/codegen-attrs.rs b/src/test/ui/hygiene/auxiliary/codegen-attrs.rs
new file mode 100644
index 0000000..74afedb
--- /dev/null
+++ b/src/test/ui/hygiene/auxiliary/codegen-attrs.rs
@@ -0,0 +1,10 @@
+#![feature(decl_macro)]
+
+macro m($f:ident) {
+    #[export_name = "export_function_name"]
+    pub fn $f() -> i32 {
+        2
+    }
+}
+
+m!(rust_function_name);
diff --git a/src/test/ui/hygiene/cross-crate-codegen-attrs.rs b/src/test/ui/hygiene/cross-crate-codegen-attrs.rs
new file mode 100644
index 0000000..af6b133
--- /dev/null
+++ b/src/test/ui/hygiene/cross-crate-codegen-attrs.rs
@@ -0,0 +1,12 @@
+// Make sure that macro expanded codegen attributes work across crates.
+// We used to gensym the identifiers in attributes, which stopped dependent
+// crates from seeing them, resulting in linker errors in cases like this one.
+
+// run-pass
+// aux-build:codegen-attrs.rs
+
+extern crate codegen_attrs;
+
+fn main() {
+    assert_eq!(codegen_attrs::rust_function_name(), 2);
+}
diff --git a/src/test/ui/hygiene/no_implicit_prelude.stderr b/src/test/ui/hygiene/no_implicit_prelude.stderr
index a89176f..643f803 100644
--- a/src/test/ui/hygiene/no_implicit_prelude.stderr
+++ b/src/test/ui/hygiene/no_implicit_prelude.stderr
@@ -1,3 +1,11 @@
+error: cannot find macro `panic!` in this scope
+  --> $DIR/no_implicit_prelude.rs:16:9
+   |
+LL |         assert_eq!(0, 0);
+   |         ^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
 error[E0433]: failed to resolve: use of undeclared type or module `Vec`
   --> $DIR/no_implicit_prelude.rs:11:9
    |
@@ -7,14 +15,6 @@
 LL |         Vec::new();
    |         ^^^ use of undeclared type or module `Vec`
 
-error: cannot find macro `panic!` in this scope
-  --> $DIR/no_implicit_prelude.rs:16:9
-   |
-LL |         assert_eq!(0, 0);
-   |         ^^^^^^^^^^^^^^^^^
-   |
-   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
-
 error[E0599]: no method named `clone` found for type `()` in the current scope
   --> $DIR/no_implicit_prelude.rs:12:12
    |
diff --git a/src/test/ui/imports/local-modularized-tricky-fail-1.stderr b/src/test/ui/imports/local-modularized-tricky-fail-1.stderr
index 5afdd88..7d01382 100644
--- a/src/test/ui/imports/local-modularized-tricky-fail-1.stderr
+++ b/src/test/ui/imports/local-modularized-tricky-fail-1.stderr
@@ -21,25 +21,6 @@
    |     ^^^^^^^^^
    = help: consider adding an explicit import of `exported` to disambiguate
 
-error[E0659]: `include` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
-  --> $DIR/local-modularized-tricky-fail-1.rs:46:1
-   |
-LL | include!();
-   | ^^^^^^^ ambiguous name
-   |
-   = note: `include` could refer to a macro from prelude
-note: `include` could also refer to the macro defined here
-  --> $DIR/local-modularized-tricky-fail-1.rs:17:5
-   |
-LL | /     macro_rules! include {
-LL | |         () => ()
-LL | |     }
-   | |_____^
-...
-LL |       define_include!();
-   |       ------------------ in this macro invocation
-   = help: use `crate::include` to refer to this macro unambiguously
-
 error[E0659]: `panic` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
   --> $DIR/local-modularized-tricky-fail-1.rs:35:5
    |
@@ -59,6 +40,25 @@
    |       ---------------- in this macro invocation
    = help: use `crate::panic` to refer to this macro unambiguously
 
+error[E0659]: `include` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
+  --> $DIR/local-modularized-tricky-fail-1.rs:46:1
+   |
+LL | include!();
+   | ^^^^^^^ ambiguous name
+   |
+   = note: `include` could refer to a macro from prelude
+note: `include` could also refer to the macro defined here
+  --> $DIR/local-modularized-tricky-fail-1.rs:17:5
+   |
+LL | /     macro_rules! include {
+LL | |         () => ()
+LL | |     }
+   | |_____^
+...
+LL |       define_include!();
+   |       ------------------ in this macro invocation
+   = help: use `crate::include` to refer to this macro unambiguously
+
 error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0659`.
diff --git a/src/test/ui/imports/shadow_builtin_macros.stderr b/src/test/ui/imports/shadow_builtin_macros.stderr
index c84226e..2f2ab20 100644
--- a/src/test/ui/imports/shadow_builtin_macros.stderr
+++ b/src/test/ui/imports/shadow_builtin_macros.stderr
@@ -14,20 +14,6 @@
    = help: or use `self::panic` to refer to this macro unambiguously
 
 error[E0659]: `panic` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
-  --> $DIR/shadow_builtin_macros.rs:20:14
-   |
-LL |     fn f() { panic!(); }
-   |              ^^^^^ ambiguous name
-   |
-   = note: `panic` could refer to a macro from prelude
-note: `panic` could also refer to the macro imported here
-  --> $DIR/shadow_builtin_macros.rs:19:26
-   |
-LL |     ::two_macros::m!(use foo::panic;);
-   |                          ^^^^^^^^^^
-   = help: use `self::panic` to refer to this macro unambiguously
-
-error[E0659]: `panic` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
   --> $DIR/shadow_builtin_macros.rs:33:5
    |
 LL |     panic!();
@@ -62,6 +48,20 @@
 LL | #[macro_use(n)]
    |             ^
 
+error[E0659]: `panic` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
+  --> $DIR/shadow_builtin_macros.rs:20:14
+   |
+LL |     fn f() { panic!(); }
+   |              ^^^^^ ambiguous name
+   |
+   = note: `panic` could refer to a macro from prelude
+note: `panic` could also refer to the macro imported here
+  --> $DIR/shadow_builtin_macros.rs:19:26
+   |
+LL |     ::two_macros::m!(use foo::panic;);
+   |                          ^^^^^^^^^^
+   = help: use `self::panic` to refer to this macro unambiguously
+
 error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0659`.
diff --git a/src/test/ui/include-macros/data.bin b/src/test/ui/include-macros/data.bin
new file mode 100644
index 0000000..ce4e0b8
--- /dev/null
+++ b/src/test/ui/include-macros/data.bin
@@ -0,0 +1,2 @@
+﻿This file starts with BOM.
+Lines are separated by \r\n.
diff --git a/src/test/ui/include-macros/normalization.rs b/src/test/ui/include-macros/normalization.rs
new file mode 100644
index 0000000..889f08e
--- /dev/null
+++ b/src/test/ui/include-macros/normalization.rs
@@ -0,0 +1,12 @@
+// run-pass
+
+fn main() {
+    assert_eq!(
+        &include_bytes!("data.bin")[..],
+        &b"\xEF\xBB\xBFThis file starts with BOM.\r\nLines are separated by \\r\\n.\r\n"[..],
+    );
+    assert_eq!(
+        include_str!("data.bin"),
+        "\u{FEFF}This file starts with BOM.\r\nLines are separated by \\r\\n.\r\n",
+    );
+}
diff --git a/src/test/ui/issues/issue-49074.stderr b/src/test/ui/issues/issue-49074.stderr
index c557255..e0d3bb3 100644
--- a/src/test/ui/issues/issue-49074.stderr
+++ b/src/test/ui/issues/issue-49074.stderr
@@ -1,9 +1,3 @@
-error: cannot find attribute macro `marco_use` in this scope
-  --> $DIR/issue-49074.rs:3:3
-   |
-LL | #[marco_use] // typo
-   |   ^^^^^^^^^ help: a built-in attribute with a similar name exists: `macro_use`
-
 error: cannot find macro `bar!` in this scope
   --> $DIR/issue-49074.rs:12:4
    |
@@ -12,5 +6,11 @@
    |
    = help: have you added the `#[macro_use]` on the module/import?
 
+error: cannot find attribute macro `marco_use` in this scope
+  --> $DIR/issue-49074.rs:3:3
+   |
+LL | #[marco_use] // typo
+   |   ^^^^^^^^^ help: a built-in attribute with a similar name exists: `macro_use`
+
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/macros/trace-macro.stderr b/src/test/ui/macros/trace-macro.stderr
index 287f7b2..202a923 100644
--- a/src/test/ui/macros/trace-macro.stderr
+++ b/src/test/ui/macros/trace-macro.stderr
@@ -5,5 +5,5 @@
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expanding `println! { "Hello, World!" }`
-   = note: to `{ $crate :: io :: _print (format_args_nl ! ("Hello, World!")) ; }`
+   = note: to `{ $crate :: io :: _print ($crate :: format_args_nl ! ("Hello, World!")) ; }`
 
diff --git a/src/test/ui/proc-macro/macro-namespace-reserved-2.stderr b/src/test/ui/proc-macro/macro-namespace-reserved-2.stderr
index b2f1247..0c863e9 100644
--- a/src/test/ui/proc-macro/macro-namespace-reserved-2.stderr
+++ b/src/test/ui/proc-macro/macro-namespace-reserved-2.stderr
@@ -88,18 +88,6 @@
 LL | #[derive(crate::my_macro)]
    |          ^^^^^^^^^^^^^^^ not a derive macro
 
-error: cannot find attribute macro `my_macro` in this scope
-  --> $DIR/macro-namespace-reserved-2.rs:38:3
-   |
-LL | #[my_macro]
-   |   ^^^^^^^^
-
-error: cannot find derive macro `my_macro` in this scope
-  --> $DIR/macro-namespace-reserved-2.rs:48:10
-   |
-LL | #[derive(my_macro)]
-   |          ^^^^^^^^
-
 error: cannot find macro `my_macro_attr!` in this scope
   --> $DIR/macro-namespace-reserved-2.rs:28:5
    |
@@ -112,5 +100,17 @@
 LL |     MyTrait!();
    |     ^^^^^^^
 
+error: cannot find attribute macro `my_macro` in this scope
+  --> $DIR/macro-namespace-reserved-2.rs:38:3
+   |
+LL | #[my_macro]
+   |   ^^^^^^^^
+
+error: cannot find derive macro `my_macro` in this scope
+  --> $DIR/macro-namespace-reserved-2.rs:48:10
+   |
+LL | #[derive(my_macro)]
+   |          ^^^^^^^^
+
 error: aborting due to 19 previous errors
 
diff --git a/src/test/ui/reserved/reserved-attr-on-macro.stderr b/src/test/ui/reserved/reserved-attr-on-macro.stderr
index d4b97d2..856162b 100644
--- a/src/test/ui/reserved/reserved-attr-on-macro.stderr
+++ b/src/test/ui/reserved/reserved-attr-on-macro.stderr
@@ -7,12 +7,6 @@
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
 
-error: cannot find attribute macro `rustc_attribute_should_be_reserved` in this scope
-  --> $DIR/reserved-attr-on-macro.rs:1:3
-   |
-LL | #[rustc_attribute_should_be_reserved]
-   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 error: cannot determine resolution for the macro `foo`
   --> $DIR/reserved-attr-on-macro.rs:10:5
    |
@@ -21,6 +15,12 @@
    |
    = note: import resolution is stuck, try simplifying macro imports
 
+error: cannot find attribute macro `rustc_attribute_should_be_reserved` in this scope
+  --> $DIR/reserved-attr-on-macro.rs:1:3
+   |
+LL | #[rustc_attribute_should_be_reserved]
+   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/rfc1598-generic-associated-types/shadowing.rs b/src/test/ui/rfc1598-generic-associated-types/shadowing.rs
index 0349263..f5197fd 100644
--- a/src/test/ui/rfc1598-generic-associated-types/shadowing.rs
+++ b/src/test/ui/rfc1598-generic-associated-types/shadowing.rs
@@ -1,12 +1,9 @@
+#![allow(incomplete_features)]
 #![feature(generic_associated_types)]
 
-//FIXME(#44265): The lifetime shadowing and type parameter shadowing
-// should cause an error. Now it compiles (erroneously) and this will be addressed
-// by a future PR. Then remove the following:
-// build-pass (FIXME(62277): could be check-pass?)
-
 trait Shadow<'a> {
-    type Bar<'a>; // Error: shadowed lifetime
+    //FIXME(#44265): The lifetime parameter shadowing should cause an error.
+    type Bar<'a>;
 }
 
 trait NoShadow<'a> {
@@ -14,11 +11,12 @@
 }
 
 impl<'a> NoShadow<'a> for &'a u32 {
-    type Bar<'a> = i32; // Error: shadowed lifetime
+    //FIXME(#44265): The lifetime parameter shadowing should cause an error.
+    type Bar<'a> = i32;
 }
 
 trait ShadowT<T> {
-    type Bar<T>; // Error: shadowed type parameter
+    type Bar<T>; //~ ERROR the name `T` is already used
 }
 
 trait NoShadowT<T> {
@@ -26,7 +24,7 @@
 }
 
 impl<T> NoShadowT<T> for Option<T> {
-    type Bar<T> = i32; // Error: shadowed type parameter
+    type Bar<T> = i32; //~ ERROR the name `T` is already used
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc1598-generic-associated-types/shadowing.stderr b/src/test/ui/rfc1598-generic-associated-types/shadowing.stderr
index 9526df2..a06c635 100644
--- a/src/test/ui/rfc1598-generic-associated-types/shadowing.stderr
+++ b/src/test/ui/rfc1598-generic-associated-types/shadowing.stderr
@@ -1,8 +1,19 @@
-warning: the feature `generic_associated_types` is incomplete and may cause the compiler to crash
-  --> $DIR/shadowing.rs:1:12
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/shadowing.rs:19:14
    |
-LL | #![feature(generic_associated_types)]
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
+LL | trait ShadowT<T> {
+   |               - first use of `T`
+LL |     type Bar<T>;
+   |              ^ already used
 
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/shadowing.rs:27:14
+   |
+LL | impl<T> NoShadowT<T> for Option<T> {
+   |      - first use of `T`
+LL |     type Bar<T> = i32;
+   |              ^ already used
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0403`.
diff --git a/src/test/ui/rust-unstable-column-gated.rs b/src/test/ui/rust-unstable-column-gated.rs
deleted file mode 100644
index 053806e..0000000
--- a/src/test/ui/rust-unstable-column-gated.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-fn main() {
-    println!("{}", __rust_unstable_column!());
-    //~^ ERROR use of unstable library feature '__rust_unstable_column'
-}
diff --git a/src/test/ui/rust-unstable-column-gated.stderr b/src/test/ui/rust-unstable-column-gated.stderr
deleted file mode 100644
index 7db1b01..0000000
--- a/src/test/ui/rust-unstable-column-gated.stderr
+++ /dev/null
@@ -1,11 +0,0 @@
-error[E0658]: use of unstable library feature '__rust_unstable_column': internal implementation detail of the `panic` macro
-  --> $DIR/rust-unstable-column-gated.rs:2:20
-   |
-LL |     println!("{}", __rust_unstable_column!());
-   |                    ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: add `#![feature(__rust_unstable_column)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr
index 94646c2..e33001b9 100644
--- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr
+++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn a(self: Pin<&Foo>, f: &Foo) -> &Foo { f }
    |                                             ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:10:50
@@ -30,7 +30,7 @@
 LL |     async fn bar<'a>(self: Alias<&Self>, arg: &'a ()) -> &() { arg }
    |                                                          ^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:19:62
diff --git a/src/test/ui/self/elision/lt-ref-self-async.nll.stderr b/src/test/ui/self/elision/lt-ref-self-async.nll.stderr
index 779b21e..3e58c97 100644
--- a/src/test/ui/self/elision/lt-ref-self-async.nll.stderr
+++ b/src/test/ui/self/elision/lt-ref-self-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn ref_self(&self, f: &u32) -> &u32 {
    |                                          ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:15:47
@@ -24,7 +24,7 @@
 LL |     async fn ref_Self(self: &Self, f: &u32) -> &u32 {
    |                                                ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:21:53
@@ -44,7 +44,7 @@
 LL |     async fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 {
    |                                                         ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:25:62
@@ -64,7 +64,7 @@
 LL |     async fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 {
    |                                                         ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:29:62
@@ -84,7 +84,7 @@
 LL |     async fn box_box_ref_Self(self: Box<Box<&Self>>, f: &u32) -> &u32 {
    |                                                                  ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:33:71
@@ -104,7 +104,7 @@
 LL |     async fn box_pin_Self(self: Box<Pin<&Self>>, f: &u32) -> &u32 {
    |                                                              ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#28r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#23r
 
 error: lifetime may not live long enough
   --> $DIR/lt-ref-self-async.rs:37:67
diff --git a/src/test/ui/self/elision/ref-mut-self-async.nll.stderr b/src/test/ui/self/elision/ref-mut-self-async.nll.stderr
index cfe91dd..b8a5380 100644
--- a/src/test/ui/self/elision/ref-mut-self-async.nll.stderr
+++ b/src/test/ui/self/elision/ref-mut-self-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn ref_self(&mut self, f: &u32) -> &u32 {
    |                                              ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:15:51
@@ -24,7 +24,7 @@
 LL |     async fn ref_Self(self: &mut Self, f: &u32) -> &u32 {
    |                                                    ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:21:57
@@ -44,7 +44,7 @@
 LL |     async fn box_ref_Self(self: Box<&mut Self>, f: &u32) -> &u32 {
    |                                                             ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:25:66
@@ -64,7 +64,7 @@
 LL |     async fn pin_ref_Self(self: Pin<&mut Self>, f: &u32) -> &u32 {
    |                                                             ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:29:66
@@ -84,7 +84,7 @@
 LL |     async fn box_box_ref_Self(self: Box<Box<&mut Self>>, f: &u32) -> &u32 {
    |                                                                      ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:33:75
@@ -104,7 +104,7 @@
 LL |     async fn box_pin_ref_Self(self: Box<Pin<&mut Self>>, f: &u32) -> &u32 {
    |                                                                      ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-self-async.rs:37:75
diff --git a/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr b/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr
index 98fa5e2..cee008d 100644
--- a/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr
+++ b/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn ref_Struct(self: &mut Struct, f: &u32) -> &u32 {
    |                                                        ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct-async.rs:15:61
@@ -24,7 +24,7 @@
 LL |     async fn box_ref_Struct(self: Box<&mut Struct>, f: &u32) -> &u32 {
    |                                                                 ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct-async.rs:19:70
@@ -44,7 +44,7 @@
 LL |     async fn pin_ref_Struct(self: Pin<&mut Struct>, f: &u32) -> &u32 {
    |                                                                 ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct-async.rs:23:70
@@ -64,7 +64,7 @@
 LL |     async fn box_box_ref_Struct(self: Box<Box<&mut Struct>>, f: &u32) -> &u32 {
    |                                                                          ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct-async.rs:27:79
@@ -84,7 +84,7 @@
 LL |     async fn box_pin_ref_Struct(self: Box<Pin<&mut Struct>>, f: &u32) -> &u32 {
    |                                                                          ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-mut-struct-async.rs:31:79
diff --git a/src/test/ui/self/elision/ref-self-async.nll.stderr b/src/test/ui/self/elision/ref-self-async.nll.stderr
index f991f6d..c3c1548 100644
--- a/src/test/ui/self/elision/ref-self-async.nll.stderr
+++ b/src/test/ui/self/elision/ref-self-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn ref_self(&self, f: &u32) -> &u32 {
    |                                          ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:24:47
@@ -24,7 +24,7 @@
 LL |     async fn ref_Self(self: &Self, f: &u32) -> &u32 {
    |                                                ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:30:53
@@ -44,7 +44,7 @@
 LL |     async fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 {
    |                                                         ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:34:62
@@ -64,7 +64,7 @@
 LL |     async fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 {
    |                                                         ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:38:62
@@ -84,7 +84,7 @@
 LL |     async fn box_box_ref_Self(self: Box<Box<&Self>>, f: &u32) -> &u32 {
    |                                                                  ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:42:71
@@ -104,7 +104,7 @@
 LL |     async fn box_pin_ref_Self(self: Box<Pin<&Self>>, f: &u32) -> &u32 {
    |                                                                  ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:46:71
@@ -124,7 +124,7 @@
 LL |     async fn wrap_ref_Self_Self(self: Wrap<&Self, Self>, f: &u8) -> &u8 {
    |                                                                     ^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-self-async.rs:50:73
diff --git a/src/test/ui/self/elision/ref-struct-async.nll.stderr b/src/test/ui/self/elision/ref-struct-async.nll.stderr
index 437d403..ff50f68 100644
--- a/src/test/ui/self/elision/ref-struct-async.nll.stderr
+++ b/src/test/ui/self/elision/ref-struct-async.nll.stderr
@@ -4,7 +4,7 @@
 LL |     async fn ref_Struct(self: &Struct, f: &u32) -> &u32 {
    |                                                    ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct-async.rs:15:57
@@ -24,7 +24,7 @@
 LL |     async fn box_ref_Struct(self: Box<&Struct>, f: &u32) -> &u32 {
    |                                                             ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct-async.rs:19:66
@@ -44,7 +44,7 @@
 LL |     async fn pin_ref_Struct(self: Pin<&Struct>, f: &u32) -> &u32 {
    |                                                             ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct-async.rs:23:66
@@ -64,7 +64,7 @@
 LL |     async fn box_box_ref_Struct(self: Box<Box<&Struct>>, f: &u32) -> &u32 {
    |                                                                      ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct-async.rs:27:75
@@ -84,7 +84,7 @@
 LL |     async fn box_pin_Struct(self: Box<Pin<&Struct>>, f: &u32) -> &u32 {
    |                                                                  ^^^^
    |
-   = note: hidden type `impl std::future::Future` captures lifetime '_#18r
+   = note: hidden type `impl std::future::Future` captures lifetime '_#15r
 
 error: lifetime may not live long enough
   --> $DIR/ref-struct-async.rs:31:71
diff --git a/src/test/ui/shadowed/shadowed-type-parameter.rs b/src/test/ui/shadowed/shadowed-type-parameter.rs
index ba9f3ab..e74620f 100644
--- a/src/test/ui/shadowed/shadowed-type-parameter.rs
+++ b/src/test/ui/shadowed/shadowed-type-parameter.rs
@@ -6,7 +6,7 @@
 
 impl<T> Foo<T> {
     fn shadow_in_method<T>(&self) {}
-    //~^ ERROR type parameter `T` shadows another type parameter
+    //~^ ERROR the name `T` is already used
 
     fn not_shadow_in_item<U>(&self) {
         struct Bar<T, U>(T,U); // not a shadow, separate item
@@ -18,10 +18,10 @@
     fn dummy(&self) -> T;
 
     fn shadow_in_required<T>(&self);
-    //~^ ERROR type parameter `T` shadows another type parameter
+    //~^ ERROR the name `T` is already used
 
     fn shadow_in_provided<T>(&self) {}
-    //~^ ERROR type parameter `T` shadows another type parameter
+    //~^ ERROR the name `T` is already used
 
     fn not_shadow_in_required<U>(&self);
     fn not_shadow_in_provided<U>(&self) {}
diff --git a/src/test/ui/shadowed/shadowed-type-parameter.stderr b/src/test/ui/shadowed/shadowed-type-parameter.stderr
index 6b4d1fa..0ea82f9 100644
--- a/src/test/ui/shadowed/shadowed-type-parameter.stderr
+++ b/src/test/ui/shadowed/shadowed-type-parameter.stderr
@@ -1,29 +1,29 @@
-error[E0194]: type parameter `T` shadows another type parameter of the same name
-  --> $DIR/shadowed-type-parameter.rs:20:27
-   |
-LL | trait Bar<T> {
-   |           - first `T` declared here
-...
-LL |     fn shadow_in_required<T>(&self);
-   |                           ^ shadows another type parameter
-
-error[E0194]: type parameter `T` shadows another type parameter of the same name
-  --> $DIR/shadowed-type-parameter.rs:23:27
-   |
-LL | trait Bar<T> {
-   |           - first `T` declared here
-...
-LL |     fn shadow_in_provided<T>(&self) {}
-   |                           ^ shadows another type parameter
-
-error[E0194]: type parameter `T` shadows another type parameter of the same name
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
   --> $DIR/shadowed-type-parameter.rs:8:25
    |
 LL | impl<T> Foo<T> {
-   |      - first `T` declared here
+   |      - first use of `T`
 LL |     fn shadow_in_method<T>(&self) {}
-   |                         ^ shadows another type parameter
+   |                         ^ already used
+
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/shadowed-type-parameter.rs:20:27
+   |
+LL | trait Bar<T> {
+   |           - first use of `T`
+...
+LL |     fn shadow_in_required<T>(&self);
+   |                           ^ already used
+
+error[E0403]: the name `T` is already used for a generic parameter in this item's generic parameters
+  --> $DIR/shadowed-type-parameter.rs:23:27
+   |
+LL | trait Bar<T> {
+   |           - first use of `T`
+...
+LL |     fn shadow_in_provided<T>(&self) {}
+   |                           ^ already used
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0194`.
+For more information about this error, try `rustc --explain E0403`.
diff --git a/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs
new file mode 100644
index 0000000..d625199
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.rs
@@ -0,0 +1,3 @@
+fn main() {
+    assert_eq!(10u64, 10usize); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr
new file mode 100644
index 0000000..f043069
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-try_into-in-macros.stderr
@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/dont-suggest-try_into-in-macros.rs:2:5
+   |
+LL |     assert_eq!(10u64, 10usize);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u64, found usize
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/symbol-names/impl1.rs b/src/test/ui/symbol-names/impl1.rs
index 52bb118..137b72d 100644
--- a/src/test/ui/symbol-names/impl1.rs
+++ b/src/test/ui/symbol-names/impl1.rs
@@ -64,9 +64,9 @@
             //[legacy]~^ ERROR symbol-name(_ZN198_$LT$$u5b$$RF$dyn$u20$impl1..Foo$u2b$Assoc$u20$$u3d$$u20$extern$u20$$u22$C$u22$$u20$fn$LP$$RF$u8$RP$$u2b$impl1..AutoTrait$u3b$$u20$_$u5d$$u20$as$u20$impl1..main..$u7b$$u7b$closure$u7d$$u7d$..Bar$GT$6method
             //[legacy]~| ERROR demangling(<[&dyn impl1::Foo+Assoc = extern "C" fn(&u8)+impl1::AutoTrait; _] as impl1::main::{{closure}}::Bar>::method
             //[legacy]~| ERROR demangling-alt(<[&dyn impl1::Foo+Assoc = extern "C" fn(&u8)+impl1::AutoTrait; _] as impl1::main::{{closure}}::Bar>::method)
-             //[v0]~^^^^ ERROR symbol-name(_RNvXNCNvCs4fqI2P2rA04_5impl14mains_0ARDNtB6_3Foop5AssocFG0_KCRL0_hEuNtB6_9AutoTraitEL_j3_NtB2_3Bar6method)
-                //[v0]~| ERROR demangling(<[&dyn impl1[317d481089b8c8fe]::Foo<Assoc = for<'a, 'b> extern "C" fn(&'b u8)> + impl1[317d481089b8c8fe]::AutoTrait; 3: usize] as impl1[317d481089b8c8fe]::main::{closure#1}::Bar>::method)
-                //[v0]~| ERROR demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a, 'b> extern "C" fn(&'b u8)> + impl1::AutoTrait; 3] as impl1::main::{closure#1}::Bar>::method)
+             //[v0]~^^^^ ERROR symbol-name(_RNvXNCNvCs4fqI2P2rA04_5impl14mains_0ARDNtB6_3Foop5AssocFG_KCRL0_hEuNtB6_9AutoTraitEL_j3_NtB2_3Bar6method)
+                //[v0]~| ERROR demangling(<[&dyn impl1[317d481089b8c8fe]::Foo<Assoc = for<'a> extern "C" fn(&'a u8)> + impl1[317d481089b8c8fe]::AutoTrait; 3: usize] as impl1[317d481089b8c8fe]::main::{closure#1}::Bar>::method)
+                //[v0]~| ERROR demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a> extern "C" fn(&'a u8)> + impl1::AutoTrait; 3] as impl1::main::{closure#1}::Bar>::method)
             #[rustc_def_path]
             //[legacy]~^ ERROR def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8)> + AutoTrait; _] as main::{{closure}}#1::Bar>::method)
                //[v0]~^^ ERROR def-path(<[&dyn Foo<Assoc = for<'r> extern "C" fn(&'r u8)> + AutoTrait; _] as main::{{closure}}#1::Bar>::method)
diff --git a/src/test/ui/symbol-names/impl1.v0.stderr b/src/test/ui/symbol-names/impl1.v0.stderr
index 1c4b256..e024799 100644
--- a/src/test/ui/symbol-names/impl1.v0.stderr
+++ b/src/test/ui/symbol-names/impl1.v0.stderr
@@ -46,19 +46,19 @@
 LL |         #[rustc_def_path]
    |         ^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_RNvXNCNvCs4fqI2P2rA04_5impl14mains_0ARDNtB6_3Foop5AssocFG0_KCRL0_hEuNtB6_9AutoTraitEL_j3_NtB2_3Bar6method)
+error: symbol-name(_RNvXNCNvCs4fqI2P2rA04_5impl14mains_0ARDNtB6_3Foop5AssocFG_KCRL0_hEuNtB6_9AutoTraitEL_j3_NtB2_3Bar6method)
   --> $DIR/impl1.rs:63:13
    |
 LL |             #[rustc_symbol_name]
    |             ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(<[&dyn impl1[317d481089b8c8fe]::Foo<Assoc = for<'a, 'b> extern "C" fn(&'b u8)> + impl1[317d481089b8c8fe]::AutoTrait; 3: usize] as impl1[317d481089b8c8fe]::main::{closure#1}::Bar>::method)
+error: demangling(<[&dyn impl1[317d481089b8c8fe]::Foo<Assoc = for<'a> extern "C" fn(&'a u8)> + impl1[317d481089b8c8fe]::AutoTrait; 3: usize] as impl1[317d481089b8c8fe]::main::{closure#1}::Bar>::method)
   --> $DIR/impl1.rs:63:13
    |
 LL |             #[rustc_symbol_name]
    |             ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a, 'b> extern "C" fn(&'b u8)> + impl1::AutoTrait; 3] as impl1::main::{closure#1}::Bar>::method)
+error: demangling-alt(<[&dyn impl1::Foo<Assoc = for<'a> extern "C" fn(&'a u8)> + impl1::AutoTrait; 3] as impl1::main::{closure#1}::Bar>::method)
   --> $DIR/impl1.rs:63:13
    |
 LL |             #[rustc_symbol_name]
diff --git a/src/test/ui/symbol-names/issue-60925.legacy.stderr b/src/test/ui/symbol-names/issue-60925.legacy.stderr
index 7fcd2ed..de8efdd 100644
--- a/src/test/ui/symbol-names/issue-60925.legacy.stderr
+++ b/src/test/ui/symbol-names/issue-60925.legacy.stderr
@@ -4,13 +4,13 @@
 LL |         #[rustc_symbol_name]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo::h059a991a004536ad)
+error: demangling(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo::h059a991a004536ad)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling-alt(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo)
+error: demangling-alt(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]
diff --git a/src/test/ui/symbol-names/issue-60925.rs b/src/test/ui/symbol-names/issue-60925.rs
index 89de15c..0243835 100644
--- a/src/test/ui/symbol-names/issue-60925.rs
+++ b/src/test/ui/symbol-names/issue-60925.rs
@@ -20,8 +20,8 @@
     impl Foo<::llvm::Foo> {
         #[rustc_symbol_name]
         //[legacy]~^ ERROR symbol-name(_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo
-        //[legacy]~| ERROR demangling(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo
-        //[legacy]~| ERROR demangling-alt(issue_60925::foo::Foo<issue_60925::llv$u6d$..Foo$GT$::foo)
+        //[legacy]~| ERROR demangling(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo
+        //[legacy]~| ERROR demangling-alt(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo)
          //[v0]~^^^^ ERROR symbol-name(_RNvMNtCs4fqI2P2rA04_11issue_609253fooINtB2_3FooNtNtB4_4llvm3FooE3foo)
             //[v0]~| ERROR demangling(<issue_60925[317d481089b8c8fe]::foo::Foo<issue_60925[317d481089b8c8fe]::llvm::Foo>>::foo)
             //[v0]~| ERROR demangling-alt(<issue_60925::foo::Foo<issue_60925::llvm::Foo>>::foo)
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 05cfdf1..3da6be7 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1659,10 +1659,10 @@
             _ if self.config.target.contains("vxworks") => {
                 let aux_dir = self.aux_output_dir_name();
                 let ProcArgs { prog, args } = self.make_run_args();
-                let mut vx_run = Command::new("vx-run");
-                vx_run.args(&[&prog]).args(args).envs(env.clone());
+                let mut wr_run = Command::new("wr-run");
+                wr_run.args(&[&prog]).args(args).envs(env.clone());
                 self.compose_and_run(
-                    vx_run,
+                    wr_run,
                     self.config.run_lib_path.to_str().unwrap(),
                     Some(aux_dir.to_str().unwrap()),
                     None,
diff --git a/src/tools/miri b/src/tools/miri
index c1cb249..4f6f264 160000
--- a/src/tools/miri
+++ b/src/tools/miri
@@ -1 +1 @@
-Subproject commit c1cb24969e84dfaded2769ab5575effc8d4f5c30
+Subproject commit 4f6f264c305ea30f1de90ad0c2f341e84d972b2e
diff --git a/src/tools/rls b/src/tools/rls
index 7b0a20b..496c892 160000
--- a/src/tools/rls
+++ b/src/tools/rls
@@ -1 +1 @@
-Subproject commit 7b0a20bf13b7061b1eb31a058117ac5517ff8cc9
+Subproject commit 496c89275221303a4b0c2779cb8203fb3ce2a136