Rank-2 polymorphism & type inference

[Simon Peyton-Jones]

| reported the bug several months ago.)  

Sorry! The bug has been fixed, but our nhc98 installation hasn't
been rebuilt.

| If your nhc98 compiler
| was built by gcc, hbc, or nhc98 itself, then it gives a proper error
| message here, viz:
| 
|     Couldn't simplify the context ((_180#) _171).
|     Possible sources for the problem are:11:20

No cigar!  What is Joe Programmer going to do with that?

But seriously, it's interesting that nhc fails in the same way as
GHC and Hugs.

Simon