diff --git a/include/toml11/fwd/comments_fwd.hpp b/include/toml11/fwd/comments_fwd.hpp
index cd5be7f..cd5bf0f 100644
--- a/include/toml11/fwd/comments_fwd.hpp
+++ b/include/toml11/fwd/comments_fwd.hpp
@@ -444,7 +444,7 @@ inline bool operator>=(const discard_comments&, const discard_comments&) noexcep
 
 inline void swap(const discard_comments&, const discard_comments&) noexcept {return;}
 
-inline std::ostream& operator<<(std::ostream&& os, const discard_comments&) {return os;}
+inline std::ostream& operator<<(std::ostream& os, const discard_comments&) {return os;}
 
 } // toml11
 #endif // TOML11_COMMENTS_FWD_HPP