Merge from rustc

Author: The Miri Cronjob Bot

tests/fail/rustc-error2.rs

@@ -4,7 +4,7 @@ struct Struct<T>(T);
 impl<T> std::ops::Deref for Struct<T> {
     type Target = dyn Fn(T);
     fn deref(&self) -> &assert_mem_uninitialized_valid::Target {
-        //~^ERROR: undeclared crate or module
+        //~^ERROR: use of unresolved module or unlinked crate
         unimplemented!()
     }
 }

tests/fail/rustc-error2.stderr

@@ -1,8 +1,10 @@
-error[E0433]: failed to resolve: use of undeclared crate or module `assert_mem_uninitialized_valid`
+error[E0433]: failed to resolve: use of unresolved module or unlinked crate `assert_mem_uninitialized_valid`
   --> tests/fail/rustc-error2.rs:LL:CC
    |
 LL |     fn deref(&self) -> &assert_mem_uninitialized_valid::Target {
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `assert_mem_uninitialized_valid`
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `assert_mem_uninitialized_valid`
+   |
+   = help: you might be missing a crate named `assert_mem_uninitialized_valid`
 
 error: aborting due to 1 previous error