Internal Parser Error for default this-parameter

[xcf-t]

Creating a method with a parameter that is assigned the default value of this will result in an internal parser error.

Running this minimal example

class Test {
  public:
    function test(argument = this) {
      return 4;
    }
}

will result in the following error:

error in line undefined: internal parser error; Cannot read property 'petype' of null

The simplest solution to this problem would probably be to disallow this as a default parameter.