Opt<T> missing destructor calls of inner type T

[johannst]

Hi,

I wanted to report, when using Opt<T> there are some cases where the number of destructor calls of the inner type do not match the number of constructor calls.

See the following reproducer (attached tarball for convenience).

// emplace.cc
#include <rpp/base.h>
#include <rpp/opt.h>

#include "printer.h"

int main() {
    rpp::Opt<printer> o1;

    o1.emplace();
    o1.emplace();
}

// output:
// printer::printer()
// printer::printer()
// printer::~printer()

// move_assign.cc
#include <rpp/base.h>
#include <rpp/opt.h>

#include "printer.h"

int main() {
    rpp::Opt<printer> o1;
    rpp::Opt<printer> o2;

    o1.emplace();
    o2 = rpp::move(o1);
}

// output:
// printer::printer()
// printer::printer(printer &&)
// printer::~printer()

// move_construct.cc
#include <rpp/base.h>
#include <rpp/opt.h>

#include "printer.h"

int main() {
    rpp::Opt<printer> o1;
    o1.emplace();

    rpp::Opt<printer> o2(rpp::move(o1));
}

// output:
// printer::printer()
// printer::printer(printer &&)
// printer::~printer()