I don't understand what's confusing with my example aha. Current situation: you have std::variant<int, whatever> x; you now want to discriminate on when

I don't understand what's confusing with my example aha. Current situation: you have std::variant<int, whatever> x; you now want to discriminate on whenever x has been initialized explicitly or not, the two cases I posted: // case 1 std::variant<int, whatever> x; // case 2 std::variant<int, whatever> x = 0; you have two options: option A: does not needlessly increase sizeof, does not add indirection penalty upon access: std::variant<std::monostate, int, whatever> x; option B: needlessly increases sizeof, adds indirection penalty upon access (mostly relevant when compiling in debug mode without inlining if you still want to have a semblance of performance): std::optional<std::variant<int, whatever>> x;