patch applied (ghc): Fix Trac #4302, plus a little refactoring

Mon Sep 13 13:04:40 EDT 2010

Mon Sep 13 10:03:55 PDT 2010  simonpj at microsoft.com
  * Fix Trac #4302, plus a little refactoring

    M ./compiler/hsSyn/HsUtils.lhs -13 +1
    M ./compiler/typecheck/TcDeriv.lhs -12 +19
    M ./compiler/typecheck/TcGenDeriv.lhs -28 +48

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20100913170355-1287e-c0ebb869f11ecb16ab9b61317d39b0174c099655.gz