Implement proper support for polymorphism

[josefs]

Implement proper support for polymorphism

[gomoripeti]

Hi Tim,

the problem is not Elixir specific. erlang:get_module_info/1 has the spec defined in erlang.erl as:

-spec erlang:get_module_info(Module) -> [{Item, term()}] when
      Item :: module | exports | attributes | compile | native | md5,
      Module :: atom().

The Module type variable is not yet resolved to atom() based on the constraints after when. This is a feature that will probably be implemented later in Gradualizer.

[tim2CF]

thanks!

[josefs]

Peter is exactly right. Type variables are not treated correctly in the current implementation. It's something I'm working on right now, but it's a bit of a thorny issue. I've renamed the issue, and I'll close it once I've implemented the support.

[tim2CF]

Thank you guys for your work!
I hope I'll also be able to contribute to this project someday :)

[zuiderkwast]

Is the problem in the example solved by #93?

[timCF]

Yes, this was fixed, thanks!

[zuiderkwast]

I'm closing this issue then, although I can't say we have "proper support for polymorphism" yet. It is broad topic. (See e.g. the discussion in #93.)