isEqVar :: Var -> Bool
-- Is lifted coercion variable (only!)
isEqVar v = case tyConAppTyCon_maybe (varType v) of
               Just tc -> tc `hasKey` eqTyConKey
               Nothing -> False
isEqVar :: Var -> Bool
isEqVar v = case tyConAppTyCon_maybe (varType v) of
               Just tc -> tc `hasKey` eqTyConKey
               Nothing -> False
isEqVar v = case tyConAppTyCon_maybe (varType v) of
               Just tc -> tc `hasKey` eqTyConKey
               Nothing -> False