save-analysis: handle paths in type/trait context more correctly

TBH, this is still not perfect, witness the FIXME, but it is an improvement. In particular it means we get information about trait references in impls.

src/librustc_save_analysis/dump_visitor.rs

@@ -470,9 +470,8 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
             if !self.span.filter_generated(Some(trait_ref_data.span), trait_ref.path.span) {
                 self.dumper.type_ref(trait_ref_data.lower(self.tcx));
             }
-
-            visit::walk_path(self, &trait_ref.path);
         }
+        self.process_path(trait_ref.ref_id, &trait_ref.path, Some(recorder::TypeRef));
     }
 
     fn process_struct_field_def(&mut self, field: &ast::StructField, parent_id: NodeId) {
@@ -756,8 +755,6 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
                 if !self.span.filter_generated(Some(trait_ref_data.span), item.span) {
                     self.dumper.type_ref(trait_ref_data.clone().lower(self.tcx));
                 }
-
-                visit::walk_path(self, &trait_ref.as_ref().unwrap().path);
             }
 
             if !self.span.filter_generated(Some(impl_data.span), item.span) {
@@ -773,6 +770,9 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
         if !has_self_ref {
             self.visit_ty(&typ);
         }
+        if let &Some(ref trait_ref) = trait_ref {
+            self.process_path(trait_ref.ref_id, &trait_ref.path, Some(recorder::TypeRef));
+        }
         self.process_generic_params(type_parameters, item.span, "", item.id);
         for impl_item in impl_items {
             let map = &self.tcx.map;
@@ -1001,8 +1001,8 @@ impl<'l, 'tcx: 'l, 'll, D: Dump + 'll> DumpVisitor<'l, 'tcx, 'll, D> {
 
     fn process_pat(&mut self, p: &'l ast::Pat) {
         match p.node {
-            PatKind::Struct(ref path, ref fields, _) => {
-                visit::walk_path(self, path);
+            PatKind::Struct(ref _path, ref fields, _) => {
+                // FIXME do something with _path?
                 let adt = match self.save_ctxt.tables.node_id_to_type_opt(p.id) {
                     Some(ty) => ty.ty_adt_def().unwrap(),
                     None => {
@@ -1359,8 +1359,6 @@ impl<'l, 'tcx: 'l, 'll, D: Dump +'ll> Visitor<'l> for DumpVisitor<'l, 'tcx, 'll,
                 }
 
                 self.write_sub_paths_truncated(path);
-
-                visit::walk_path(self, path);
             }
             ast::TyKind::Array(ref element, ref length) => {
                 self.visit_ty(element);