--- a/src/luan/LuanClosure.java	Thu Oct 22 00:33:04 2020 -0600
+++ b/src/luan/LuanClosure.java	Thu Nov 05 20:24:09 2020 -0700
@@ -21,6 +21,11 @@
 		super.completeClone(dc,cloner);
 	}
 
+	@Override public void makeImmutable(LuanImmutabler immutabler) throws LuanException {
+		immutabler.makeImmutable(upValues);
+		super.makeImmutable(immutabler);
+	}
+
 	@Override public final Object call(Object... args) throws LuanException {
 		Luan luan = luan();
 		luan.push(this);