Review changes

Author: nrc

src/librustc_typeck/astconv.rs

@@ -73,6 +73,11 @@ pub trait AstConv<'tcx> {
     fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx>;
     fn get_item_ty(&self, id: ast::DefId) -> ty::Polytype<'tcx>;
     fn get_trait_def(&self, id: ast::DefId) -> Rc<ty::TraitDef<'tcx>>;
+
+    /// Return an (optional) substitution to convert bound type parameters that
+    /// are in scope into free ones. This function should only return Some
+    /// within a fn body.
+    /// See ParameterEnvironment::free_substs for more information.
     fn get_free_substs(&self) -> Option<&Substs<'tcx>> {
         None
     }
@@ -1029,21 +1034,15 @@ pub fn ast_ty_to_ty<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
                         // FIXME(#19541): in both branches we should consider
                         // associated types in super-traits.
                         let (assoc_tys, tp_name): (Vec<_>, _) = match typ {
-                            def::TyParamProvenance::FromParam(did) => {
+                            def::TyParamProvenance::FromParam(did) |
+                            def::TyParamProvenance::FromSelf(did) => {
                                 let ty_param_defs = tcx.ty_param_defs.borrow();
                                 let tp_def = &(*ty_param_defs)[did.node];
                                 let assoc_tys = tp_def.bounds.trait_bounds.iter()
                                     .filter_map(|b| find_assoc_ty(this, &**b, assoc_ident))
                                     .collect();
                                 (assoc_tys, token::get_name(tp_def.name).to_string())
                             }
-                            def::TyParamProvenance::FromSelf(did) => {
-                                let assoc_tys = find_assoc_ty(this,
-                                                              &*this.get_trait_def(did).trait_ref,
-                                                              assoc_ident)
-                                    .into_iter().collect();
-                                (assoc_tys, "Self".to_string())
-                            }
                         };
 
                         if assoc_tys.len() == 0 {