diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 0af32c8fe6d..334ef30487a 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -355,7 +355,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         self.tcx.associated_items(def_id).find(|item| item.name == item_name)
     }
 
-    fn matches_return_type(&self, method: &ty::ImplOrTraitItem<'tcx>,
+    pub fn matches_return_type(&self, method: &ty::ImplOrTraitItem<'tcx>,
                            expected: ty::Ty<'tcx>) -> bool {
         match *method {
             ty::ImplOrTraitItem::MethodTraitItem(ref x) => {
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 32de37764f6..85a2fcd2ba1 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -626,16 +626,6 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         Ok(())
     }
 
-    fn matches_return_type(&self, method: &ty::ImplOrTraitItem<'tcx>,
-                           expected: &ty::Ty<'tcx>) -> bool {
-        match *method {
-            ty::ImplOrTraitItem::MethodTraitItem(ref x) => {
-                self.can_sub_types(x.fty.sig.skip_binder().output, expected).is_ok()
-            }
-            _ => false,
-        }
-    }
-
     fn assemble_extension_candidates_for_trait(&mut self,
                                                trait_def_id: DefId)
                                                -> Result<(), MethodError<'tcx>> {
@@ -652,7 +642,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
             LookingFor::ReturnType(item_ty) => {
                 trait_items.iter()
                            .find(|item| {
-                                self.matches_return_type(item, &item_ty)
+                                self.fcx.matches_return_type(item, &item_ty)
                             })
             }
         };