which may be true in general, but there is the special case that these two interfaces have a relationship (i.e. one extends the other). In that case, the code would compile fine (as was proven to me (the hard wayHowever, you still cannot have a class that implements two interfaces where both the interfaces contain a default method with the same signature unless the class provides an implementation for that method itself.

I would suggest to add this exceptional case to the description just to make it complete