Integrity checker for CPS and Tree IR.

pkg/compiler/lib/src/tree_ir/tree_ir_tracer.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library tree_ir_tracer;
 
 import 'dart:async' show EventSink;
 import '../tracer.dart';
 import 'tree_ir_nodes.dart';
 import 'optimization/optimization.dart';
@@ skipping 166 matching lines @@
   }
 
   visitSetField(SetField node) {
     _addStatement(node);
     visitStatement(node.next);
   }
 
 }
 
 class TreeTracer extends TracerUtil with StatementVisitor, PassMixin {
+  // TODO(asgerf): Fix visitors so we don't have to use PassMixin here.
+  String get passName => null;
+
   final EventSink<String> output;
 
   TreeTracer(this.output);
 
   Names names;
   BlockCollector collector;
   int statementCounter;
 
   void traceGraph(String name, ExecutableDefinition node) {
     if (node is FunctionDefinition && node.isAbstract) return;
@@ skipping 312 matching lines @@
       String prefix = v.element == null ? 'v' : '${v.element.name}_';
       while (name == null || _usedNames.contains(name)) {
         name = "$prefix${_counter++}";
       }
       _names[v] = name;
       _usedNames.add(name);
     }
     return name;
   }
 }