mutable_wrapper

mutable_wrapper.hpp

#include <vector>
#include <iterator>

struct X {
    X() = default;
    X(X&&) = default;
    X(X const&) = delete;
};

template<typename Val>
struct mutable_wrapper {
    mutable Val value;
    
    constexpr operator Val&() const&
    { return value; }
    
    constexpr operator Val&&() const&&
    { return std::move(value); }
};

template<typename Val>
constexpr mutable_wrapper<Val> mut(Val&& val)
{ return { std::forward<Val>(val) }; }

int main() {
    auto xs = { mut(X {}), mut(X {}), mut(X {}) };
    auto xv = std::vector<X> { std::make_move_iterator(begin(xs)), std::make_move_iterator(end(xs)) };
}