Switch next-solver related rustc dependencies of r-a to crates.io ones
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/lib.rs b/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
index 301d4cc..e5c213c 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
@@ -15,10 +15,6 @@
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_parse_format as rustc_parse_format;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_abi;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_abi as rustc_abi;
 
 pub mod db;
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
index 451622e..2e59a48 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
@@ -3,45 +3,24 @@
 
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_index;
+// FIXME: We used to import `rustc_*` deps from `rustc_private` with `feature = "in-rust-tree" but
+// temporarily switched to crates.io versions due to hardships that working on them from rustc
+// demands corresponding changes on rust-analyzer at the same time.
+// For details, see the zulip discussion below:
+// https://rust-lang.zulipchat.com/#narrow/channel/185405-t-compiler.2Frust-analyzer/topic/relying.20on.20in-tree.20.60rustc_type_ir.60.2F.60rustc_next_trait_solver.60/with/541055689
 
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_index as rustc_index;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_abi;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_abi as rustc_abi;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_pattern_analysis;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_pattern_analysis as rustc_pattern_analysis;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_ast_ir;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_ast_ir as rustc_ast_ir;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_type_ir;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_type_ir as rustc_type_ir;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_next_trait_solver;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_next_trait_solver as rustc_next_trait_solver;
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_data_structures as ena;
-
 mod builder;
 mod chalk_db;
 mod chalk_ext;
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/consts.rs b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/consts.rs
index 7ebefa7..0b35820 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/consts.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/consts.rs
@@ -36,8 +36,6 @@ pub fn new(interner: DbInterner<'db>, kind: ConstKind<'db>) -> Self {
             internee: kind,
             flags: flags.flags,
             outer_exclusive_binder: flags.outer_exclusive_binder,
-            #[cfg(feature = "in-rust-tree")]
-            stable_hash: ena::fingerprint::Fingerprint::ZERO,
         };
         Const::new_(interner.db(), InternedWrapperNoDebug(cached))
     }
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/predicate.rs b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/predicate.rs
index 8654541..99b1354 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/predicate.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/predicate.rs
@@ -227,8 +227,6 @@ pub fn new(interner: DbInterner<'db>, kind: Binder<'db, PredicateKind<'db>>) ->
             internee: kind,
             flags: flags.flags,
             outer_exclusive_binder: flags.outer_exclusive_binder,
-            #[cfg(feature = "in-rust-tree")]
-            stable_hash: ena::fingerprint::Fingerprint::ZERO,
         };
         Predicate::new_(interner.db(), InternedWrapperNoDebug(cached))
     }
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/ty.rs b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/ty.rs
index c7a747a..70139e8 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/ty.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/next_solver/ty.rs
@@ -60,8 +60,6 @@ pub fn new(interner: DbInterner<'db>, kind: TyKind<'db>) -> Self {
             internee: kind,
             flags: flags.flags,
             outer_exclusive_binder: flags.outer_exclusive_binder,
-            #[cfg(feature = "in-rust-tree")]
-            stable_hash: ena::fingerprint::Fingerprint::ZERO,
         };
         Ty::new_(interner.db(), InternedWrapperNoDebug(cached))
     }
diff --git a/src/tools/rust-analyzer/crates/hir/src/lib.rs b/src/tools/rust-analyzer/crates/hir/src/lib.rs
index f8dacf0..027a386 100644
--- a/src/tools/rust-analyzer/crates/hir/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/lib.rs
@@ -20,10 +20,6 @@
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![recursion_limit = "512"]
 
-#[cfg(feature = "in-rust-tree")]
-extern crate rustc_type_ir;
-
-#[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_type_ir as rustc_type_ir;
 
 mod attrs;