patch applied (ghc-6.6/ghc): MERGED: Match the type of an Id during rule matching

[Ian Lynagh]

Sun Apr  1 06:28:38 PDT 2007  Ian Lynagh <igloo at earth.li>
  * MERGED: Match the type of an Id during rule matching
  simonpj at microsoft.com**20070330140033
   
          Please MERGE to 6.6.1
   
   Consider this RULE
       forall (c::Char->Int) (x::Char). 
          f (c x) = "RULE FIRED"
   
   Well, this should only match on arguments of the specified type
   But we simply weren't checking this condition before.  Now we are.
   
   Test is simplrun008

    M ./compiler/specialise/Rules.lhs -4 +21