Haskell98 undefinedness

[Simon Peyton-Jones]

Personally I think this is ok, and it's compatible with the=20
relaxed story about cumulative imports.  I don't propose
to change this unless there are yells.

| So, it's not considered an error if you do something
| like
|=20
|   module A ( B(C), ...some other stuff..., B(D) ) where=20
|   ...
|   data B =3D C | D=20
|=20
| but C and D is exported. Is the extra flexibility of
| allowing duplicates really worth it?

Simon