+ let is_identity_goal = function
+ | _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> Some []
+ | _, Terms.Equation (l,r,_,_), vl, proof ->
+ (try Some (Unif.unification (* vl *) [] l r)
+ with FoUnif.UnificationFailure _ -> None)
+ | _, Terms.Equation (_,_,_,_), _, _ -> None
+ | _, Terms.Predicate _, _, _ -> assert false
+ ;;
+