WIP rebase for shallow_resolve call

Author: nikomatsakis

src/librustc_typeck/check/closure.rs

@@ -663,7 +663,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // be inferring.
         let ret_ty = ret_coercion.borrow().expected_ty();
         let ret_ty = self.inh.infcx.shallow_resolve(ret_ty);
-        let ret_vid = match ret_ty.sty {
+        let ret_vid = match ret_ty.kind {
             ty::Infer(ty::TyVar(ret_vid)) => ret_vid,
             _ => {
                 span_bug!(