http://bugs.winehq.org/show_bug.cgi?id=31724
--- Comment #15 from Nikolay Sivov bunglehead@gmail.com --- Created attachment 47749 --> http://bugs.winehq.org/attachment.cgi?id=47749 test.idl
I think it's a widl bug. It's easy to reproduce with attached idl. The problem is that when forward interface declaration is present widl creates 2 typeinfos for 'enum' that look identical, plus 1 typeinfo for interface. Without a forward it creates one typeinfo for enum and one for interface. In first situation some internal referencing breaks so method argument is unable to locate its type.