I think then we need to replace this by expand instead of expand_once. Otherwise if you have a macro this macro:

defmacro current_module do
  quote do
    __MODULE__
  end
end

and this typespec:

current_module().Foo.Bar

It will no longer work, as the first expansion will return __MODULE__.

I think then we need to replace this by expand instead of expand_once.

Done in 3abb13b

It will no longer work,

Just FYI, I checked and this was an infinite loop as well so technically it did never worked (we were returning the pre-expansion alias as is and kept looping). I agree we should fix it of course.