1 files changed, 10 insertions, 8 deletions

diff --git a/tuplr.hpp b/tuplr.hpp
index a9f244c..1984f6e 100644
--- a/tuplr.hpp
+++ b/tuplr.hpp
@@ -260,6 +260,9 @@ struct AType : public ATuple {
 		}
 		return true;
 	}
+	bool operator<(const AType& rhs) const {
+		return kind < rhs.kind || id < rhs.id;
+	}
 	bool operator==(const AST& rhs) const {
 		const AType* rt = rhs.to<const AType*>();
 		if (!rt || kind != rt->kind)
@@ -431,8 +434,8 @@ inline ostream& operator<<(ostream& out, const Constraints& c) {
 	return out;
 }
 	
-struct Subst : public map<const AType*,AType*> {
-	Subst(AType* s=0, AType* t=0) { if (s && t) { assert(s != t); insert(make_pair(s, t)); } }
+struct Subst : public map<const AType,AType*> {
+	Subst(AType* s=0, AType* t=0) { if (s && t) { assert(s != t); insert(make_pair(*s, t)); } }
 	static Subst compose(const Subst& delta, const Subst& gamma);
 	AST* apply(AST* ast) const {
 		AType* in = ast->to<AType*>();
@@ -443,13 +446,12 @@ struct Subst : public map<const AType*,AType*> {
 				out->push_back(apply(in->at(i)));
 			return out;
 		} else {
-			Subst copy(*this);
-			iterator i;
-			while ((i = copy.find(in)) != copy.end()) {
-				in = i->second;
-				copy.erase(i);
+			const_iterator i = find(*in);
+			if (i != end()) {
+				return i->second;
+			} else {
+				return in;
 			}
-			return in;
 		}
 	}
 };