Use better bound names in -Zverbose mode

src/librustc/infer/error_reporting/mod.rs

@@ -1778,8 +1778,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
 
         let mut err = match *sub {
-            ty::ReEarlyBound(_)
-            | ty::ReFree(ty::FreeRegion { bound_region: ty::BrNamed(..), .. }) => {
+            ty::ReEarlyBound(ty::EarlyBoundRegion { name, .. })
+            | ty::ReFree(ty::FreeRegion { bound_region: ty::BrNamed(_, name), .. }) => {
                 // Does the required lifetime have a nice name we can print?
                 let mut err = struct_span_err!(
                     self.tcx.sess,
@@ -1788,7 +1788,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     "{} may not live long enough",
                     labeled_user_string
                 );
-                binding_suggestion(&mut err, type_param_span, bound_kind, sub);
+                // Explicitely use the name instead of `sub`'s `Display` impl. The `Display` impl
+                // for the bound is not suitable for suggestions when `-Zverbose` is set because it
+                // uses `Debug` output, so we handle it specially here so that suggestions are
+                // always correct.
+                binding_suggestion(&mut err, type_param_span, bound_kind, name);
                 err
             }
 

src/test/ui/nll/closure-requirements/propagate-from-trait-match.stderr

@@ -45,7 +45,7 @@ LL | |         require(value);
 LL | |     });
    | |_____^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: aborting due to previous error
 

src/test/ui/nll/ty-outlives/impl-trait-outlives.stderr

@@ -4,15 +4,15 @@ error[E0309]: the parameter type `T` may not live long enough
 LL | fn no_region<'a, T>(x: Box<T>) -> impl Debug + 'a
    |                                   ^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/impl-trait-outlives.rs:22:42
    |
 LL | fn wrong_region<'a, 'b, T>(x: Box<T>) -> impl Debug + 'a
    |                                          ^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: aborting due to 2 previous errors
 

src/test/ui/nll/ty-outlives/projection-no-regions-closure.stderr

@@ -31,7 +31,7 @@ error[E0309]: the associated type `<T as std::iter::Iterator>::Item` may not liv
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: 'a`...
 
 note: external requirements
   --> $DIR/projection-no-regions-closure.rs:34:23
@@ -92,7 +92,7 @@ error[E0309]: the associated type `<T as std::iter::Iterator>::Item` may not liv
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: 'a`...
 
 note: external requirements
   --> $DIR/projection-no-regions-closure.rs:52:23

src/test/ui/nll/ty-outlives/projection-no-regions-fn.stderr

@@ -4,15 +4,15 @@ error[E0309]: the associated type `<T as std::iter::Iterator>::Item` may not liv
 LL |     Box::new(x.next())
    |     ^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: 'a`...
 
 error[E0309]: the associated type `<T as std::iter::Iterator>::Item` may not live long enough
   --> $DIR/projection-no-regions-fn.rs:28:5
    |
 LL |     Box::new(x.next())
    |     ^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `<T as std::iter::Iterator>::Item: 'a`...
 
 error: aborting due to 2 previous errors
 

src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr

@@ -33,7 +33,7 @@ error[E0309]: the parameter type `T` may not live long enough
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0:15 ~ projection_one_region_closure[317d]::no_relationships_late[0]), BrNamed(DefId(0:16 ~ projection_one_region_closure[317d]::no_relationships_late[0]::'a[0]), 'a))`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: lifetime may not live long enough
   --> $DIR/projection-one-region-closure.rs:45:39
@@ -82,7 +82,7 @@ error[E0309]: the parameter type `T` may not live long enough
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: lifetime may not live long enough
   --> $DIR/projection-one-region-closure.rs:56:39

src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr

@@ -32,7 +32,7 @@ error[E0309]: the associated type `<T as Anything<'_#5r, '_#6r>>::AssocType` may
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as Anything<'_#5r, '_#6r>>::AssocType: ReFree(DefId(0:17 ~ projection_two_region_trait_bound_closure[317d]::no_relationships_late[0]), BrNamed(DefId(0:18 ~ projection_two_region_trait_bound_closure[317d]::no_relationships_late[0]::'a[0]), 'a))`...
+   = help: consider adding an explicit lifetime bound `<T as Anything<'_#5r, '_#6r>>::AssocType: 'a`...
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:48:29
@@ -67,7 +67,7 @@ error[E0309]: the associated type `<T as Anything<'_#6r, '_#7r>>::AssocType` may
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as Anything<'_#6r, '_#7r>>::AssocType: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `<T as Anything<'_#6r, '_#7r>>::AssocType: 'a`...
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:61:29

src/test/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr

@@ -53,7 +53,7 @@ error[E0309]: the parameter type `T` may not live long enough
 LL |     twice(cell, value, |a, b| invoke(a, b));
    |                        ^^^^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0:12 ~ ty_param_closure_approximate_lower_bound[317d]::generic_fail[0]), BrNamed(DefId(0:13 ~ ty_param_closure_approximate_lower_bound[317d]::generic_fail[0]::'a[0]), 'a))`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: aborting due to previous error
 

src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr

@@ -31,15 +31,15 @@ error[E0309]: the parameter type `T` may not live long enough
 LL |     with_signature(x, |y| y)
    |                       ^^^^^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/ty-param-closure-outlives-from-return-type.rs:41:5
    |
 LL |     x
    |     ^
    |
-   = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 error: aborting due to 2 previous errors
 

src/test/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr

@@ -46,7 +46,7 @@ LL | |         require(&x, &y)
 LL | |     })
    | |_____^
    |
-   = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0:11 ~ ty_param_closure_outlives_from_where_clause[317d]::no_region[0]), BrNamed(DefId(0:12 ~ ty_param_closure_outlives_from_where_clause[317d]::no_region[0]::'a[0]), 'a))`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 note: external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:43:26
@@ -126,7 +126,7 @@ LL | |         require(&x, &y)
 LL | |     })
    | |_____^
    |
-   = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0:19 ~ ty_param_closure_outlives_from_where_clause[317d]::wrong_region[0]), BrNamed(DefId(0:20 ~ ty_param_closure_outlives_from_where_clause[317d]::wrong_region[0]::'a[0]), 'a))`...
+   = help: consider adding an explicit lifetime bound `T: 'a`...
 
 note: external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:77:26