import CmdLineOpts ( opt_AllowOverlappingInstances )
import TcMonad
-import TcEnv ( InstEnv, emptyInstEnv, addToInstEnv )
+--import TcEnv ( InstEnv, emptyInstEnv, addToInstEnv )
import Bag ( bagToList, Bag )
import Class ( Class )
import Var ( TyVar, Id, idName )