rails/rails — pull request #13450 by chancancode (2013-12-22 13:35:36+00:00)
Title: Raise an error if `scope` or `enum` is about too add a conflicting method to the class

See #13389 for details. I left out case 4, because that does not particularly concerns me, and I don't think checking `klass.new.respond_to?(...)` is a good idea.

cc @senny @dhh