@@ -22,19 +22,19 @@
 
 template DeriveCompare()
 {
 override:
-	bool opEquals(Object rhs)
+	bool opEquals(Object rhs) const
 	{
 		return tuple(this.tupleof) == tuple((cast(typeof(this))rhs).tupleof);
 	}
 
-	int opCmp(Object rhs)
+	int opCmp(Object rhs) const
 	{
 		return tuple(this.tupleof).opCmp(tuple((cast(typeof(this))rhs).tupleof));
 	}
 
-	hash_t toHash()
+	hash_t toHash() const
 	{
 		hash_t v = 0;
 		foreach(mem; this.tupleof) {
 			v *= 11;
@@ -49,9 +49,9 @@
 
 template DeriveShow()
 {
 override:
-	string toString()
+	string toString() const
 	{
 		string str = text(typeof(this).stringof, "(");
 		foreach(i,mem; this.tupleof) {
 			if(i) str ~= ", ";