https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78490
--- Comment #2 from Felix Morgner <felix.morgner at gmail dot com> --- Comment on attachment 40124 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40124 Proposed patch >--- propagate_const.org 2016-11-23 10:28:45.682529129 +0100 >+++ propagate_const.new 2016-11-23 10:28:27.076012689 +0100 >@@ -153,6 +153,7 @@ > constexpr propagate_const& operator=(propagate_const<_Up>&& __pu) > { > _M_t = std::move(get_underlying(__pu)); >+ return *this; > } > > template <typename _Up, typename = >@@ -163,6 +164,7 @@ > constexpr propagate_const& operator=(_Up&& __u) > { > _M_t = std::forward<_Up>(__u); >+ return *this; > } > > // [propagate_const.const_observers], const observers
