Rollup merge of #46282 - estebank:impl-trait-cicle-span, r=arielb1

Shorten output of E0391

Use the shorter `def_span` on the impl-Trait cyclic reference errors.

Author: kennytm

src/librustc/ty/maps/plumbing.rs

@@ -81,17 +81,18 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // (And cycle errors around impls tend to occur during the
         // collect/coherence phases anyhow.)
         item_path::with_forced_impl_filename_line(|| {
+            let span = self.sess.codemap().def_span(span);
             let mut err =
                 struct_span_err!(self.sess, span, E0391,
                                  "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/compile-fail/impl-trait/auto-trait-leak.rs renamed to src/test/ui/impl-trait/auto-trait-leak.rs

@@ -0,0 +1,52 @@
+error[E0277]: the trait bound `std::rc::Rc<std::cell::Cell<i32>>: std::marker::Send` is not satisfied in `impl std::ops::Fn<(i32,)>`
+  --> $DIR/auto-trait-leak.rs:27:5
+   |
+27 |     send(before());
+   |     ^^^^ `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
+   |
+   = help: within `impl std::ops::Fn<(i32,)>`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
+   = note: required because it appears within the type `[closure@$DIR/auto-trait-leak.rs:21:5: 21:22 p:std::rc::Rc<std::cell::Cell<i32>>]`
+   = note: required because it appears within the type `impl std::ops::Fn<(i32,)>`
+   = note: required by `send`
+
+error[E0277]: the trait bound `std::rc::Rc<std::cell::Cell<i32>>: std::marker::Send` is not satisfied in `impl std::ops::Fn<(i32,)>`
+  --> $DIR/auto-trait-leak.rs:34:5
+   |
+34 |     send(after());
+   |     ^^^^ `std::rc::Rc<std::cell::Cell<i32>>` cannot be sent between threads safely
+   |
+   = help: within `impl std::ops::Fn<(i32,)>`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::cell::Cell<i32>>`
+   = note: required because it appears within the type `[closure@$DIR/auto-trait-leak.rs:46:5: 46:22 p:std::rc::Rc<std::cell::Cell<i32>>]`
+   = note: required because it appears within the type `impl std::ops::Fn<(i32,)>`
+   = note: required by `send`
+
+error[E0391]: unsupported cyclic reference between types/traits detected
+  --> $DIR/auto-trait-leak.rs:52:1
+   |
+52 | fn cycle1() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ cyclic reference
+   |
+note: the cycle begins when processing `cycle1`...
+  --> $DIR/auto-trait-leak.rs:52:1
+   |
+52 | fn cycle1() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which then requires processing `cycle2::{{impl-Trait}}`...
+  --> $DIR/auto-trait-leak.rs:63:16
+   |
+63 | fn cycle2() -> impl Clone {
+   |                ^^^^^^^^^^
+note: ...which then requires processing `cycle2`...
+  --> $DIR/auto-trait-leak.rs:63:1
+   |
+63 | fn cycle2() -> impl Clone {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: ...which then requires processing `cycle1::{{impl-Trait}}`...
+  --> $DIR/auto-trait-leak.rs:52:16
+   |
+52 | fn cycle1() -> impl Clone {
+   |                ^^^^^^^^^^
+   = note: ...which then again requires processing `cycle1`, completing the cycle.
+
+error: aborting due to 3 previous errors
+

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

@@ -8,7 +8,7 @@ note: the cycle begins when processing `<impl at $DIR/issue-23305.rs:15:1: 15:20
   --> $DIR/issue-23305.rs:15:1
    |
 15 | impl ToNbt<Self> {}
-   | ^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^
    = note: ...which then again requires processing `<impl at $DIR/issue-23305.rs:15:1: 15:20>`, completing the cycle.
 
 error: aborting due to previous error