diff --git a/src/ox/std/strongint.hpp b/src/ox/std/strongint.hpp
index 6fc37ddfb..dd7bf76e5 100644
--- a/src/ox/std/strongint.hpp
+++ b/src/ox/std/strongint.hpp
@@ -34,7 +34,7 @@ class Integer: public Base {
 
 		constexpr Integer(const Integer<T, Base> &i) noexcept;
 
-		constexpr Integer<T, Base> operator=(Integer<T, Base> i) noexcept;
+		constexpr Integer<T, Base> &operator=(Integer<T, Base> i) noexcept;
 
 		constexpr Integer<T, Base> operator==(Integer<T, Base> i) const noexcept;
 
@@ -118,7 +118,7 @@ constexpr Integer<T, Base>::Integer(const Integer<T, Base> &i) noexcept: Base(i)
 }
 
 template<typename T, class Base>
-constexpr Integer<T, Base> Integer<T, Base>::operator=(Integer<T, Base> i) noexcept {
+constexpr Integer<T, Base> &Integer<T, Base>::operator=(Integer<T, Base> i) noexcept {
 	// needed in case T has nodiscard
 	constexpr auto ignore = [](Base) {};
 	ignore(Base::operator=(i));