https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88337
--- Comment #1 from emsr at gcc dot gnu.org --- LOL, this compiles: // P1330R0 - Changing the active member of a union inside constexpr union Foo { int i; float f; }; constexpr int use() { Foo foo{}; foo.i = 3; foo.f = 1.2f; return 1; }