text: var a, b;
  
  function f1(a, b) {
      var a, b;
  }
  
  function f2(a, b = a) {
      var a;
      b;
  }
  
  function f3(a = () => b) { }
  
  function f4({a, b : b}, x = a, y = b) { }
  
  function f5(a = arguments) {
      arguments;
  }
  
  function f6(arguments) {
      function f7(a = arguments) {
          arguments;
      }
  }
  