It should be impossible to configure actual type arguments for CtTypeParameterReference

[leventov]

methods like addActualTypeArgument() should throw exception, because this is illegal things to do. But they have some logic currently in CtTypeParameterReferenceImpl.

[monperrus]

I'm not in favor of throwing an exception because it would require client code to add ugly try/catch.

however, you're right, and there should not be no code in CtTypeParameterReference.addActualTypeArgument. We'll try to remove it and replace it by an appropriate comment.