Consider trait aliases

Author: estebank

src/librustc/traits/error_reporting.rs

@@ -1029,6 +1029,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 hir::Node::Item(hir::Item {
                     kind: hir::ItemKind::TyAlias(_, generics), span, ..
                 }) |
+                hir::Node::Item(hir::Item {
+                    kind: hir::ItemKind::TraitAlias(generics, _), span, ..
+                }) |
                 hir::Node::Item(hir::Item {
                     kind: hir::ItemKind::OpaqueTy(hir::OpaqueTy { generics, .. }), span, ..
                 }) |

src/test/ui/traits/trait-alias/trait-alias-wf.stderr

@@ -4,9 +4,10 @@ error[E0277]: the trait bound `T: Foo` is not satisfied
 LL | trait A<T: Foo> {}
    | --------------- required by `A`
 LL | trait B<T> = A<T>;
-   | ^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `T`
-   |
-   = help: consider adding a `where T: Foo` bound
+   | ^^^^^^^^-^^^^^^^^^
+   | |       |
+   | |       help: consider restricting this bound: `T: Foo`
+   | the trait `Foo` is not implemented for `T`
 
 error: aborting due to previous error