diff --git a/03/ast.cpp b/03/ast.cpp
index f244ffa..bdee157 100644
--- a/03/ast.cpp
+++ b/03/ast.cpp
@@ -28,28 +28,22 @@ type_ptr ast_binop::typecheck(type_mgr& mgr, const type_env& env) const {
     type_ptr ftype = env.lookup(op_name(op));
     if(!ftype) throw 0;
 
-    type_ptr place_a = mgr.new_type();
-    type_ptr place_b = mgr.new_type();
-    type_ptr place_c = mgr.new_type();
-    type_ptr arrow_one = type_ptr(new type_arr(place_b, place_c));
-    type_ptr arrow_two = type_ptr(new type_arr(place_a, arrow_one));
+    type_ptr return_type = mgr.new_type();
+    type_ptr arrow_one = type_ptr(new type_arr(rtype, return_type));
+    type_ptr arrow_two = type_ptr(new type_arr(ltype, arrow_one));
 
     mgr.unify(arrow_two, ftype);
-    mgr.unify(place_a, ltype);
-    mgr.unify(place_b, rtype);
-    return place_c;
+    return return_type;
 }
 
 type_ptr ast_app::typecheck(type_mgr& mgr, const type_env& env) const {
     type_ptr ltype = left->typecheck(mgr, env);
     type_ptr rtype = right->typecheck(mgr, env);
 
-    type_ptr place_a = mgr.new_type();
-    type_ptr place_b = mgr.new_type();
-    type_ptr arrow = type_ptr(new type_arr(place_a, place_b));
+    type_ptr return_type = mgr.new_type();
+    type_ptr arrow = type_ptr(new type_arr(rtype, return_type));
     mgr.unify(arrow, ltype);
-    mgr.unify(place_a, rtype);
-    return place_b;
+    return return_type;
 }
 
 type_ptr ast_case::typecheck(type_mgr& mgr, const type_env& env) const {