patch applied (ghc): Fix a nasty bug in RULE matching: Trac #4814

[Simon Peyton Jones]

Thu Dec  2 02:26:18 PST 2010  simonpj at microsoft.com
  * Fix a nasty bug in RULE matching: Trac #4814
  
  See Note [Matching lets], which explains it all in detail.
  It took me a day to think of a nice way to fix the bug,
  but I think the result is quite respectable. Subtle, though.

    M ./compiler/basicTypes/VarEnv.lhs -4 +6
    M ./compiler/coreSyn/CoreSubst.lhs -3 +25
    M ./compiler/specialise/Rules.lhs -178 +234

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20101202102618-1287e-2b9ac4e8d4e032dae6a7e0d341e3f32e0dc90d5d.gz