rfc: multiple decls for functions

[FX]

> Could you elaborate a bit on the "file-scope resolution"? Seems I  
> missed your
> point there?!

It's just that unless I'm mistaken, creating decls is the translation  
stage of compilation. Resolution comes before that. So when I said  
"file-scope resolution", what I meant is identifying occurences of a  
single functions in the same file wherever they are, before even  
creating any decl at all. This is also required for file-scope  
diagnostics.

FX