patch applied (ghc): In an AbsBinds, the 'dicts' can include EqInsts

[Simon Peyton Jones]

Sat Oct 27 08:49:03 PDT 2007  simonpj at microsoft.com
  * In an AbsBinds, the 'dicts' can include EqInsts
  
  An AbsBinds abstrats over evidence, and the evidence can be both
  Dicts (class constraints, implicit parameters) and EqInsts (equality
  constraints).  So we need to
    - use varType rather than idType
    - use instToVar rather than instToId
    - use zonkDictBndr rather than zonkIdBndr in zonking
  
  It actually all worked before, but gave warnings.
  
  

    M ./compiler/typecheck/TcBinds.lhs -4 +4
    M ./compiler/typecheck/TcHsSyn.lhs -1 +8
    M ./compiler/typecheck/TcInstDcls.lhs -1 +1
    M ./compiler/typecheck/TcSimplify.lhs -3 +6