Make impl-trait ciclical reference error point to def_span

Author: estebank

src/librustc/ty/maps/plumbing.rs

@@ -86,12 +86,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                                  "unsupported cyclic reference between types/traits detected");
             err.span_label(span, "cyclic reference");
 
-            err.span_note(stack[0].0, &format!("the cycle begins when {}...",
-                                               stack[0].1.describe(self)));
+            err.span_note(self.sess.codemap().def_span(stack[0].0),
+                          &format!("the cycle begins when {}...", stack[0].1.describe(self)));
 
             for &(span, ref query) in &stack[1..] {
-                err.span_note(span, &format!("...which then requires {}...",
-                                             query.describe(self)));
+                err.span_note(self.sess.codemap().def_span(span),
+                              &format!("...which then requires {}...", query.describe(self)));
             }
 
             err.note(&format!("...which then again requires {}, completing the cycle.",

src/test/ui/impl-trait/auto-trait-leak.stderr

@@ -35,14 +35,8 @@ error[E0391]: unsupported cyclic reference between types/traits detected
 note: the cycle begins when processing `cycle1`...
   --> $DIR/auto-trait-leak.rs:52:1
    |
-52 | / fn cycle1() -> impl Clone {
-53 | |     //~^ ERROR unsupported cyclic reference between types/traits detected
-54 | |     //~| cyclic reference
-55 | |     //~| NOTE the cycle begins when processing `cycle1`...
-...  |
-60 | |     Rc::new(Cell::new(5))
-61 | | }
-   | |_^
+52 | fn cycle1() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which then requires processing `cycle2::{{impl-Trait}}`...
   --> $DIR/auto-trait-leak.rs:63:16
    |
@@ -51,14 +45,8 @@ note: ...which then requires processing `cycle2::{{impl-Trait}}`...
 note: ...which then requires processing `cycle2`...
   --> $DIR/auto-trait-leak.rs:63:1
    |
-63 | / fn cycle2() -> impl Clone {
-64 | |     //~^ NOTE ...which then requires processing `cycle2::{{impl-Trait}}`...
-65 | |     //~| NOTE ...which then requires processing `cycle2`...
-66 | |     send(cycle1().clone());
-67 | |
-68 | |     Rc::new(String::from("foo"))
-69 | | }
-   | |_^
+63 | fn cycle2() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which then requires processing `cycle1::{{impl-Trait}}`...
   --> $DIR/auto-trait-leak.rs:52:16
    |