factor out helper method

src/librustc/traits/coherence.rs

@@ -140,10 +140,7 @@ pub fn trait_ref_is_knowable<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
     // if the trait is not marked fundamental, then it's always possible that
     // an ancestor crate will impl this in the future, if they haven't
     // already
-    if
-        trait_ref.def_id.krate != LOCAL_CRATE &&
-        !tcx.has_attr(trait_ref.def_id, "fundamental")
-    {
+    if !trait_ref_is_local_or_fundamental(tcx, trait_ref) {
         debug!("trait_ref_is_knowable: trait is neither local nor fundamental");
         return false;
     }
@@ -157,6 +154,11 @@ pub fn trait_ref_is_knowable<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
     orphan_check_trait_ref(tcx, trait_ref, InferIsLocal(true)).is_err()
 }
 
+pub fn trait_ref_is_local_or_fundamental<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
+                                                         trait_ref: &ty::TraitRef<'tcx>) {
+    trait_ref.def_id.krate == LOCAL_CRATE || tcx.has_attr(trait_ref.def_id, "fundamental")
+}
+
 pub enum OrphanCheckErr<'tcx> {
     NoLocalInputType,
     UncoveredTy(Ty<'tcx>),

src/librustc/traits/select.rs

@@ -1077,9 +1077,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 } else {
                     None
                 };
-                let cause = if
-                    trait_ref.def_id.krate != LOCAL_CRATE &&
-                    !self.tcx().has_attr(trait_ref.def_id, "fundamental") {
+                let cause = if !coherence::trait_ref_is_local_or_fundamental(self.tcx(),
+                                                                             trait_ref) {
                     IntercrateAmbiguityCause::UpstreamCrateUpdate { trait_desc, self_desc }
                 } else {
                     IntercrateAmbiguityCause::DownstreamCrate { trait_desc, self_desc }