anchor.diff:      js.Statement body = unwrapStatement(currentContainer);
       currentContainer = oldContainerStack.removeLast();
   
  -    js.Statement result = new js.While(new js.LiteralBool(true), body);
  +    js.Statement result = new js.While(newLiteralBool(true), body);
       attachLocationRange(result,
                           info.loopBlockInformation.sourcePosition,
                           info.loopBlockInformation.endSourcePosition);
  
positive.code:   visitBoolify(HBoolify node) {
      assert(node.inputs.length == 1);
      use(node.inputs[0]);
      push(new js.Binary('===', pop(), new js.LiteralBool(true)), node);
    }
  
    visitExit(HExit node) {
  
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);
  