anchor.diff:  
         List<jsAst.Statement> body = <jsAst.Statement>[];
         jsAst.Statement optimizedPath =
  -          tryOptimizeOneShotInterceptor(selector, classes);
  +          fastPathForOneShotInterceptor(selector, classes);
         if (optimizedPath != null) {
           body.add(optimizedPath);
         }
  
positive.code:       String name = selector.name.stringValue;
        if (name == '==') {
          // Unfolds to:
          // [: if (receiver == null) return a0 == null;
          //    if (typeof receiver != 'object') {
          //      return a0 != null && receiver === a0;
          //    }
          // :].
          List<jsAst.Statement> body = <jsAst.Statement>[];
          body.add(js.if_('receiver == null', js.return_(js('a0 == null'))));
          body.add(js.if_(
  
negative.code:     return rtiNeededClasses;
    }
  
    // Returns a statement that takes care of performance critical
    // common case for a one-shot interceptor, or null if there is no
    // fast path.
    jsAst.Statement fastPathForOneShotInterceptor(Selector selector,
                                                  Set<ClassElement> classes) {
      jsAst.Expression isNumber(String variable) {
        return js('typeof $variable == "number"');
  