https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109482
m.cencora at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |m.cencora at gmail dot com --- Comment #4 from m.cencora at gmail dot com --- Can't you use designated initializer? https://godbolt.org/z/nWP7avK9x struct in_addr_t { void * dummy; }; struct in_addr { union { struct { char b[4]; }; in_addr_t s_addr; }; }; constexpr bool test() { in_addr a = {.s_addr = {}}; return a.s_addr.dummy == nullptr; } static_assert(test());