Do not suggest using ! with break

Author: estebank

src/librustc_typeck/check/expr.rs

@@ -559,6 +559,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             ty::Char => "'a'",
                             ty::Int(_) | ty::Uint(_) => "42",
                             ty::Float(_) => "3.14159",
+                            ty::Error | ty::Never => return,
                             _ => "value",
                         });
                         err.span_suggestion(expr.span, msg, sugg, Applicability::HasPlaceholders);

src/test/ui/loops/loop-break-value.stderr

@@ -90,10 +90,7 @@ error[E0308]: mismatched types
   --> $DIR/loop-break-value.rs:4:31
    |
 LL |     let val: ! = loop { break break; };
-   |                               ^^^^^
-   |                               |
-   |                               expected !, found ()
-   |                               help: give it a value of the expected type: `break value`
+   |                               ^^^^^ expected !, found ()
    |
    = note: expected type `!`
               found type `()`