Auto merge of #32005 - vegai:31686, r=Manishearth

Fix note for type alias in trait position

Fixes #31686

Author: bors

src/librustc_resolve/lib.rs

@@ -1988,9 +1988,12 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                                                                       path_depth)));
 
                 // If it's a typedef, give a note
-                if let Def::TyAlias(..) = path_res.base_def {
-                    err.span_note(trait_path.span,
+                if let Def::TyAlias(did) = path_res.base_def {
+                    err.fileline_note(trait_path.span,
                                   "`type` aliases cannot be used for traits");
+                    if let Some(sp) = self.ast_map.span_if_local(did) {
+                        err.span_note(sp, "type defined here");
+                    }
                 }
                 err.emit();
                 Err(())

src/test/compile-fail/issue-3907.rs

@@ -11,7 +11,7 @@
 // aux-build:issue_3907.rs
 extern crate issue_3907;
 
-type Foo = issue_3907::Foo;
+type Foo = issue_3907::Foo; //~ NOTE: type defined here
 
 struct S {
     name: isize

src/test/compile-fail/issue-5035.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 trait I {}
-type K = I;
+type K = I; //~ NOTE: type defined here
 impl K for isize {} //~ ERROR: `K` is not a trait
 //~^ NOTE: `type` aliases cannot be used for traits
 fn main() {}