+improveFromInstEnv :: (Class -> [Instance])
+ -> Pred_Loc
+ -> [(Equation,Pred_Loc,Pred_Loc)]
+-- Improvement from top-level instances
+improveFromInstEnv _inst_env pred
+ = improveOne _inst_env pred [] -- TODO: Refactor to directly use instance_eqnd?
+
+improveFromAnother :: Pred_Loc
+ -> Pred_Loc
+ -> [(Equation,Pred_Loc,Pred_Loc)]
+-- Improvement from another local (given or wanted) constraint
+improveFromAnother pred1 pred2
+ = improveOne (\_ -> []) pred1 [pred2] -- TODO: Refactor to directly use pairwise_eqns?
+
+