anchor.diff:      generateStaticGetterGet(node, getter);
     }
   
  -  void generatePossiblyConditionalInstanceSetter(ast.Send send,
  -                                                 HInstruction pushReceiver(),
  -                                                 HInstruction pushValue(),
  -                                                 {Selector selector,
  -                                                  ast.Node location}) {
  -    if (send.isConditional) {
  -      SsaBranchBuilder brancher = new SsaBranchBuilder(this, send);
  -      // compile e?.x = e2 to:
  -      //
  -      // t1 = e
  -      // if (t1 == null)
  -      //   result = t1 // same as result = null
  -      // else
  -      //   result = e.x = e2
  -      HInstruction receiver;
  -      brancher.handleConditional(
  -          () {
  -            receiver = pushReceiver();
  -            pushCheckNull(receiver);
  -          },
  -          () => stack.add(receiver),
  -          () => generateInstanceSetterWithCompiledReceiver(
  -                    send, receiver, pushValue(),
  -                    selector: selector, location: location));
  -    } else {
  -      generateInstanceSetterWithCompiledReceiver(
  -          send, pushReceiver(), pushValue(),
  -          selector: selector, location: location);
  -    }
  -  }
  -
     void generateInstanceSetterWithCompiledReceiver(ast.Send send,
                                                     HInstruction receiver,
                                                     HInstruction value,
  
positive.code:     } else if (name == 'JS_BUILTIN') {
        handleForeignJsBuiltin(node);
      } else if (name == 'JS_GET_FLAG') {
        handleForeingJsGetFlag(node);
      } else if (name == 'JS_EFFECT') {
        stack.add(graph.addConstantNull(compiler));
      } else if (name == 'JS_INTERCEPTOR_CONSTANT') {
  
negative.code:     }
    }
  
    void handleForeignJsGetFlag(ast.Send node) {
      List<ast.Node> arguments = node.arguments.toList();
       ast.Node argument;
       switch (arguments.length) {
  