diff --git a/rust/private/rust.bzl b/rust/private/rust.bzl
index f3a874a..6968187 100644
--- a/rust/private/rust.bzl
+++ b/rust/private/rust.bzl
@@ -305,7 +305,9 @@
     crate_name = compute_crate_name(ctx.workspace_name, ctx.label, toolchain, ctx.attr.crate_name)
     _assert_correct_dep_mapping(ctx)
 
-    output = ctx.actions.declare_file(ctx.label.name + toolchain.binary_ext)
+    # If the target's label contains "/" characters, we need to convert those to
+    # something safe, otherwise they get converted into path separators.
+    output = ctx.actions.declare_file(ctx.label.name.replace("/", "_") + toolchain.binary_ext)
 
     deps = transform_deps(ctx.attr.deps)
     proc_macro_deps = transform_deps(ctx.attr.proc_macro_deps + get_import_macro_deps(ctx))
diff --git a/rust/private/utils.bzl b/rust/private/utils.bzl
index 1e61993..83dbb1e 100644
--- a/rust/private/utils.bzl
+++ b/rust/private/utils.bzl
@@ -272,7 +272,9 @@
     Returns:
         str: The name of the crate for this target.
     """
-    return name.replace("-", "_")
+    for illegal in ("-", "/"):
+        name = name.replace(illegal, "_")
+    return name
 
 def _invalid_chars_in_crate_name(name):
     """Returns any invalid chars in the given crate name.
diff --git a/test/unit/crate_name/crate_name_test.bzl b/test/unit/crate_name/crate_name_test.bzl
index 968f2b5..8671951 100644
--- a/test/unit/crate_name/crate_name_test.bzl
+++ b/test/unit/crate_name/crate_name_test.bzl
@@ -48,7 +48,7 @@
 
 def _invalid_default_crate_name_test_impl(ctx):
     env = analysistest.begin(ctx)
-    asserts.expect_failure(env, "contains invalid character(s): /")
+    asserts.expect_failure(env, "contains invalid character(s): @")
     return analysistest.end(env)
 
 def _invalid_custom_crate_name_test_impl(ctx):
@@ -119,7 +119,7 @@
 
 def _crate_name_test():
     rust_library(
-        name = "default-crate-name-library",
+        name = "default/crate-name-library",
         srcs = ["lib.rs"],
         edition = "2018",
     )
@@ -132,7 +132,7 @@
     )
 
     rust_binary(
-        name = "default-crate-name-binary",
+        name = "default/crate-name-binary",
         srcs = ["main.rs"],
         edition = "2018",
     )
@@ -145,7 +145,7 @@
     )
 
     rust_test(
-        name = "default-crate-name-test",
+        name = "default/crate-name-test",
         srcs = ["main.rs"],
         edition = "2018",
     )
@@ -158,7 +158,7 @@
     )
 
     rust_library(
-        name = "invalid/default-crate-name",
+        name = "invalid@default-crate-name",
         srcs = ["lib.rs"],
         edition = "2018",
         tags = ["manual", "norustfmt"],
@@ -197,7 +197,7 @@
 
     default_crate_name_library_test(
         name = "default_crate_name_library_test",
-        target_under_test = ":default-crate-name-library",
+        target_under_test = ":default/crate-name-library",
     )
 
     custom_crate_name_library_test(
@@ -207,7 +207,7 @@
 
     default_crate_name_binary_test(
         name = "default_crate_name_binary_test",
-        target_under_test = ":default-crate-name-binary",
+        target_under_test = ":default/crate-name-binary",
     )
 
     custom_crate_name_binary_test(
@@ -217,7 +217,7 @@
 
     default_crate_name_test_test(
         name = "default_crate_name_test_test",
-        target_under_test = ":default-crate-name-test",
+        target_under_test = ":default/crate-name-test",
     )
 
     custom_crate_name_test_test(
@@ -227,7 +227,7 @@
 
     invalid_default_crate_name_test(
         name = "invalid_default_crate_name_test",
-        target_under_test = ":invalid/default-crate-name",
+        target_under_test = ":invalid@default-crate-name",
     )
 
     invalid_custom_crate_name_test(