diff -r 43ce3672648a -r 910890292639 src/main.h
--- a/src/main.h	Tue Jan 26 18:02:17 2021 +0200
+++ b/src/main.h	Fri Feb 05 14:23:16 2021 +0200
@@ -168,7 +168,7 @@
 	MapItemsIterator(Ts&&... args) : IteratorType{args...} {}
 	auto operator*() const
 	{
-		return KeyValuePair<K, V>{this->key(), this->value()};
+		return KeyValuePair<const K&, V&>{this->key(), this->value()};
 	}
 };