patch applied (ghc-6.6/ghc): MERGED: Be more relaxed about reporting ambiguous class methods

[Ian Lynagh]

Sun Mar 11 08:59:18 PDT 2007  Ian Lynagh <igloo at earth.li>
  * MERGED: Be more relaxed about reporting ambiguous class methods
  simonpj at microsoft.com**20070103160703
          (MERGE to STABLE branch, pls)
   
   This patch makes us a bit more relaxed about ambiguous 
   class method types.  See tc223 for an example.
   
   Reported by Yitzchak Gale

    M ./compiler/typecheck/TcTyClsDecls.lhs -3 +9