TL;DR: see compilers disagree on code by Godbolt link: https://godbolt.org/z/f7G6PTEsh

Should std::variant be nothrow destructible when its aternative has potentially throwing destructor? Clang and GCC seem to disagree on it (probably different standard library implementations on Godbolt?), MSVC thinks it should. cppreference says variant’s destructor does not have noexcept specifications, and in that case destructor should be unconditionally noexcept unless it has potentially throwing members or bases (https://en.cppreference.com/w/cpp/language/noexcept_spec), which is not specified for variant (duh!).

The reason I’m asking is not to mess with throwing stuff out of destructors, but to gradually refactor weird legacy stuff that is minimized to the following snippet (“exception specification of overriding function is more lax than the base version”), and also related bug on dated compiler that we can’t update yet.

#include <type_traits>
#include <variant>

struct S
{
    ~S() noexcept(false);
};

static_assert(std::is_nothrow_destructible_v<std::variant<S>>); // assertion failed with clang

struct Y
{
    virtual ~Y() {}
};

struct Z: public Y
{
    virtual ~Z() {}

    // clang error because of this member: 
    // exception specification of overriding function is more lax than the base version
    std::variant<int, S> member;
}