RE: GHC warnings

[Simon Peyton-Jones]

> And another one (only with -DDEBUG): What do the warnings
> "extendCSEnv: long list: ..." try to tell me? Am *I* doing
> something silly or ghc?  :-)

GHC now does limited common-subexpression analysis.
Exprssions are hashed, then looked up using their hash key.
The exetendCSEnv message just says that a hash bucket has
more than 4 elements.  It's just to help me improve the hashing.
Unlike the earlier things, it's not unexpected.  I'll remove it
in due course.

S