anchor.diff:  
       if (input is HBoolify && isGenerateAtUseSite(input)) {
         use(input.inputs[0]);
  -      push(new js.Binary("!==", pop(), new js.LiteralBool(true)), input);
  +      push(new js.Binary("!==", pop(), newLiteralBool(true)), input);
       } else if (canGenerateOptimizedComparison(input) &&
                  isGenerateAtUseSite(input)) {
         Map<String, String> inverseOperator = const <String, String>{
  
positive.code:     js.Statement body = currentContainer;
      currentContainer = oldContainerStack.removeLast();
      body = unwrapStatement(body);
      js.While loop = new js.While(new js.LiteralBool(true), body);
  
      HLoopInformation info = block.loopInformation;
      attachLocationRange(loop,
  
negative.code:     if (identical(element, objectClass) || identical(element, compiler.dynamicClass)) {
        // The constant folder also does this optimization, but we make
        // it safe by assuming it may have not run.
        push(newLiteralBool(true), node);
      } else if (element == compiler.stringClass) {
        checkString(input, '===');
        attachLocationToLast(node);
  