patch applied (ghc): Fix TcUnify.subFunTys in AppTy case

[Simon Peyton Jones]

Tue Jan 31 04:24:20 PST 2006  simonpj at microsoft.com
  * Fix TcUnify.subFunTys in AppTy case
  
  subFunTys wasn't dealing correctly with the case where the type
  to be split was of form (a ty1), where a is a type variable.
  
  This shows up when compiling 
  	Control.Arrow.Transformer.Stream
  in package arrows.
  
  This commit fixes it.
  
  

    M ./ghc/compiler/typecheck/TcExpr.lhs -2 +2
    M ./ghc/compiler/typecheck/TcMType.lhs -7 +10
    M ./ghc/compiler/typecheck/TcPat.lhs -2 +2
    M ./ghc/compiler/typecheck/TcUnify.lhs -10 +27