UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36

Steps to reproduce the problem:
(() => { 
  'use strict';
  function a({ eval = false } = {}) {}
})();

What is the expected behavior?
This should Throw that eval cannot be redefined in "strict mode" 

What went wrong?
This throws - 
function a() { 'use strict'; let eval = "x"; } 

But, when using Non-Simple Parameter list, it doesn't detect the binding "eval".

Did this work before? No 

Chrome version: 51.0.2704.106  Channel: stable
OS Version: OS X 10.11.5
Flash Version: