Add issue reference to E0202 message

src/librustc_typeck/collect.rs

@@ -1107,7 +1107,7 @@ fn report_assoc_ty_on_inherent_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, span:
         tcx.sess,
         span,
         E0202,
-        "associated types are not allowed in inherent impls"
+        "associated types are not yet supported in inherent impls (see #8995)"
     );
 }
 

src/test/ui/assoc-inherent.rs

@@ -1,9 +1,9 @@
-// Test associated types are forbidden in inherent impls.
+// Test associated types are, until #8995 is implemented, forbidden in inherent impls.
 
 struct Foo;
 
 impl Foo {
-    type Bar = isize; //~ERROR associated types are not allowed in inherent impls
+    type Bar = isize; //~ERROR associated types are not yet supported in inherent impls (see #8995)
 }
 
 fn main() {}

src/test/ui/assoc-inherent.stderr

@@ -1,7 +1,7 @@
-error[E0202]: associated types are not allowed in inherent impls
+error[E0202]: associated types are not yet supported in inherent impls (see #8995)
   --> $DIR/assoc-inherent.rs:6:5
    |
-LL |     type Bar = isize; //~ERROR associated types are not allowed in inherent impls
+LL |     type Bar = isize; //~ERROR associated types are not yet supported in inherent impls (see #8995)
    |     ^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error