code: function (y) {
          if (resolved) return;
          resolved = true;
          /*  [Promises/A+ 2.3.3.3.3]  */
  
          if (y === x)
            /*  [Promises/A+ 3.6]  */
            promise.reject(new TypeError('circular thenable chain'));else resolve(promise, y);
        }
docs: /*  resolvePromise /*  [Promises/A+ 2.3.3.3.1]