librustc_typeck: store a DefId rather than a Name

src/librustc/infer/error_reporting/mod.rs

@@ -899,9 +899,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             infer::LateBoundRegion(_, br, infer::HigherRankedType) => {
                 format!(" for lifetime parameter {}in generic type", br_string(br))
             }
-            infer::LateBoundRegion(_, br, infer::AssocTypeProjection(type_name)) => {
+            infer::LateBoundRegion(_, br, infer::AssocTypeProjection(def_id)) => {
                 format!(" for lifetime parameter {}in trait containing associated type `{}`",
-                        br_string(br), type_name)
+                        br_string(br), self.tcx.associated_item(def_id).name)
             }
             infer::EarlyBoundRegion(_, name) => {
                 format!(" for lifetime parameter `{}`",

src/librustc/infer/mod.rs

@@ -274,7 +274,7 @@ pub enum LateBoundRegionConversionTime {
     HigherRankedType,
 
     /// when projecting an associated type
-    AssocTypeProjection(ast::Name), // FIXME(tschottdorf): should contain DefId, not Name
+    AssocTypeProjection(DefId),
 }
 
 /// Reasons to create a region inference variable

src/librustc_typeck/check/mod.rs

@@ -1646,11 +1646,10 @@ impl<'a, 'gcx, 'tcx> AstConv<'gcx, 'tcx> for FnCtxt<'a, 'gcx, 'tcx> {
                                         poly_trait_ref: ty::PolyTraitRef<'tcx>)
                                         -> Ty<'tcx>
     {
-        let item = self.tcx().associated_item(item_def_id);
         let (trait_ref, _) =
             self.replace_late_bound_regions_with_fresh_var(
                 span,
-                infer::LateBoundRegionConversionTime::AssocTypeProjection(item.name),
+                infer::LateBoundRegionConversionTime::AssocTypeProjection(item_def_id),
                 &poly_trait_ref);
 
         self.tcx().mk_projection(item_def_id, trait_ref.substs)

src/librustc_typeck/check/regionck.rs

@@ -1805,8 +1805,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
                     let (outlives, _) =
                         self.replace_late_bound_regions_with_fresh_var(
                             span,
-                            infer::AssocTypeProjection(
-                                self.tcx.associated_item(projection_ty.item_def_id).name),
+                            infer::AssocTypeProjection(projection_ty.item_def_id),
                             &outlives);
 
                     debug!("projection_bounds: outlives={:?} (3)",