-import Name ( Name, getSrcLoc )
-import Var ( TyVar )
-import Class ( Class, FunDep, classTvsFds )
-import Unify ( tcUnifyTys, BindFlag(..) )
-import Type ( substTys, notElemTvSubst )
-import TcType ( Type, PredType(..), tcEqType,
- predTyUnique, mkClassPred, tyVarsOfTypes, tyVarsOfPred )
-import InstEnv ( Instance(..), InstEnv, instanceHead, classInstances,
- instanceCantMatch, roughMatchTcs )