auto merge of #5084 : oncemoreification/rust/issue-4517, r=brson

Patch for #4517

This works for fixed vectors, but I am unclear how slices should be printed, simply '&[...]'  or...

e.i. How should regions be printed?

diff --cc src/librustc/middle/typeck/infer/mod.rs
index b7e1b8a14ec68c73743b4ce3a7b4d0eb268c889d,55a9527213848fd0dd68ef01fc306b8d9ff450e7..b55b45a31834195c93002c5737928fed453eafe7
--- 1/src/librustc/middle/typeck/infer/mod.rs
--- 2/src/librustc/middle/typeck/infer/mod.rs
+++ b/src/librustc/middle/typeck/infer/mod.rs
@@@ -732,9 -731,8 +732,8 @@@ impl @mut InferCtxt 
               ty::note_and_explain_type_err(self.tcx, *err));
      }
  
 -    fn report_mismatched_types(sp: span, e: ty::t, a: ty::t,
 +    fn report_mismatched_types(&self, sp: span, e: ty::t, a: ty::t,
                                 err: &ty::type_err) {
-         // Don't report an error if expected is ty_err
          let resolved_expected =
              self.resolve_type_vars_if_possible(e);
          let mk_msg = match ty::get(resolved_expected).sty {