patch applied (ghc): Do less simplification when doing let-generalisation

[Simon Peyton Jones]

Fri Oct  8 06:35:42 PDT 2010  simonpj at microsoft.com
  * Do less simplification when doing let-generalisation
  
  This fixes Trac #4361.  In a rather delicate way, but
  no more delicate than before.  A more remoseless typechecker
  would reject #4361 altogether.
  
  See Note [Avoid unecessary constraint simplification]

    M ./compiler/typecheck/TcSimplify.lhs -22 +32

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20101008133542-1287e-29d50a61056042232052f1a71dc82f1b0d2256aa.gz