Add span label to E0044

Author: estebank

src/librustc_typeck/check/mod.rs

@@ -1222,6 +1222,7 @@ pub fn check_item_type<'a,'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, it: &'tcx hir::Item
                 if !generics.types.is_empty() {
                     let mut err = struct_span_err!(tcx.sess, item.span, E0044,
                         "foreign items may not have type parameters");
+                    err.span_label(item.span, "can't have type parameters");
                     // FIXME: once we start storing spans for type arguments, turn this into a
                     // suggestion.
                     err.help("use specialization instead of type parameters by replacing them \

src/test/ui/closure-move-sync.stderr

@@ -22,4 +22,4 @@ LL |     thread::spawn(|| tx.send(()).unwrap());
 
 error: aborting due to 2 previous errors
 
-If you want more information on this error, try using "rustc --explain E0277"
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/error-codes/E0044.rs

@@ -12,6 +12,7 @@ extern {
     fn sqrt<T>(f: T) -> T;
     //~^ ERROR foreign items may not have type parameters [E0044]
     //~| HELP use specialization instead of type parameters by replacing them with concrete types
+    //~| NOTE can't have type parameters
 }
 
 fn main() {

src/test/ui/error-codes/E0044.stderr

@@ -2,7 +2,7 @@ error[E0044]: foreign items may not have type parameters
   --> $DIR/E0044.rs:12:5
    |
 LL |     fn sqrt<T>(f: T) -> T;
-   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^ can't have type parameters
    |
    = help: use specialization instead of type parameters by replacing them with concrete types like `u32`