patch applied (ghc): Fix Trac #2714 (a minor wibble)

[Simon Peyton Jones]

Wed Oct 22 07:51:38 PDT 2008  simonpj at microsoft.com
  * Fix Trac #2714 (a minor wibble)
  
  In boxy_match (which is a pure function used by preSubType) we can
  encounter TyVars not just TcTyVars; this patch takes account of that.
  

    M ./compiler/typecheck/TcUnify.lhs -1 +4

View patch online:
http://darcs.haskell.org/ghc/_darcs/patches/20081022145138-1287e-10e57734a4f8933cf7f5e78dc559827002c8cf95.gz