patch applied (ghc): Make the treatment of equalities more uniform

[Simon Peyton Jones]

Mon Jan  7 06:23:06 PST 2008  simonpj at microsoft.com
  * Make the treatment of equalities more uniform
  
  This patch (which is part of the fix for Trac #2018) makes coercion variables
  be handled more uniformly.  Generally, they are treated like dictionaries
  in the type checker, not like type variables, but in a couple of places we
  were treating them like type variables.  Also when zonking we should use
  zonkDictBndr not zonkIdBndr.
  

    M ./compiler/hsSyn/HsBinds.lhs -2 +2
    M ./compiler/hsSyn/HsPat.lhs -3 +4
    M ./compiler/typecheck/TcHsSyn.lhs -2 +2
    M ./compiler/typecheck/TcMType.lhs +1
    M ./compiler/typecheck/TcSimplify.lhs -1 +1
    M ./compiler/typecheck/TcTyFuns.lhs -1 +1
    M ./compiler/typecheck/TcType.lhs -3 +1
    M ./compiler/typecheck/TcUnify.lhs -1 +1
    M ./compiler/types/FamInstEnv.lhs -1 +1
    M ./compiler/types/TypeRep.lhs -15 +22