patch applied (ghc): Recover gracefully from a Template Haskell programmers error

[Simon Peyton Jones]

Fri Apr 14 04:58:31 PDT 2006  simonpj at microsoft.com
  * Recover gracefully from a Template Haskell programmers error
  
  If a TH programmer uses a type constructor as a data constructor,
  GHC simply crashed.  This commit makes it report the error in a
  graceful way.
  

    M ./compiler/basicTypes/RdrName.lhs -5 +3
    M ./compiler/typecheck/TcEnv.lhs -8 +11
    M ./compiler/typecheck/TcExpr.lhs -4 +2