patch applied (testsuite): No pattern matching on GADTs except if type is rigid

[Simon Peyton Jones]

Wed Jan  3 02:17:15 PST 2007  simonpj at microsoft.com
  * No pattern matching on GADTs except if type is rigid
  
  GHC currnently will only pattern-match on a GADT if the scrutinee type
  is rigid.  It's kind-of possible to mactch a wobbly scrutinee if all
  the case alternatives can be made compatible, but that seems a rare case.
  
  So for now, I'm just making it illegal.
  

    M ./tests/ghc-regress/gadt/gadt13.stderr -4 +5
    M ./tests/ghc-regress/gadt/gadt7.stderr -9 +13