traits: prefer ClosureSubsts to InferCtxt::closure_kind

Author: nikomatsakis

src/librustc/traits/fulfill.rs

@@ -438,8 +438,8 @@ fn process_predicate<'a, 'gcx, 'tcx>(
             }
         }
 
-        ty::Predicate::ClosureKind(closure_def_id, _closure_substs, kind) => {
-            match selcx.infcx().closure_kind(closure_def_id) {
+        ty::Predicate::ClosureKind(closure_def_id, closure_substs, kind) => {
+            match closure_substs.opt_closure_kind(closure_def_id, selcx.tcx()) {
                 Some(closure_kind) => {
                     if closure_kind.extends(kind) {
                         Ok(Some(vec![]))

src/librustc/traits/select.rs

@@ -718,8 +718,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 }
             }
 
-            ty::Predicate::ClosureKind(closure_def_id, _closure_substs, kind) => {
-                match self.infcx.closure_kind(closure_def_id) {
+            ty::Predicate::ClosureKind(closure_def_id, closure_substs, kind) => {
+                match closure_substs.opt_closure_kind(closure_def_id, self.tcx()) {
                     Some(closure_kind) => {
                         if closure_kind.extends(kind) {
                             EvaluatedToOk