A visitor that builds a map from node to "Usage".

lib/compiler/implementation/dart_backend/backend.dart

Index: lib/compiler/implementation/dart_backend/backend.dart
diff --git a/lib/compiler/implementation/dart_backend/backend.dart b/lib/compiler/implementation/dart_backend/backend.dart
index ac03dfe86c7658f555d6a303d7397fb7859583d2..443aa6df145ba6f22bbcd04b7e5019c45e13a93f 100644
--- a/lib/compiler/implementation/dart_backend/backend.dart
+++ b/lib/compiler/implementation/dart_backend/backend.dart
@@ -70,7 +70,16 @@ class DartBackend extends Backend {
       !isDartCoreLib(compiler, element.getLibrary());
 
     try {
-      Emitter emitter = new Emitter(compiler);
+      Usager usager = new Usager(compiler);
+      resolvedElements.forEach((element, treeElements) {
+        if (!shouldOutput(element)
+            || element is SynthesizedConstructorElement

[Anton Muhin, 2012/08/07 12:32:11]

why this is not a part of shouldOutput?

and we have pretty much the same logic in Emitter.outputElement, shouldn't we
unify it?

[Roman, 2012/08/07 15:44:03]

We should, but I'm not sure what would be the nice way to do that. We don't have
this check in shouldOutput, because if we see AbstractFieldMember or
constructor, we still should call addMemberToClass(), otherwise class A that has
only constructor used, will not be emitted.

+            || element is AbstractFieldElement) return;
+        usager.process(element, treeElements);
+      });
+      ConflictingRenamer renamer =
+          new ConflictingRenamer(compiler, usager.usages);
+      Emitter emitter = new Emitter(compiler, renamer);
       resolvedElements.forEach((element, treeElements) {
         if (!shouldOutput(element)) return;
         if (element.isMember()) {