text: //// [classWithOptionalParameter.ts]
  // classes do not permit optional parameters, these are errors
  
  class C {
      x?: string;
      f?() {}
  }
  
  class C2<T> {
      x?: T;
      f?(x: T) {}
  }
  
  //// [classWithOptionalParameter.js]
  // classes do not permit optional parameters, these are errors
  var C = (function () {
      function C() {
      }
      C.prototype.f = function () { };
      return C;
  })();
  var C2 = (function () {
      function C2() {
      }
      C2.prototype.f = function (x) { };
      return C2;
  })();
  