Class Convert

test/optional_unittest.cpp:112–122

struct Obj {};

struct Convert {
    Convert()
        :default_ctor(false), move_ctor(false) { }
    explicit Convert(const Obj&)
        :default_ctor(true), move_ctor(false) { }
    explicit Convert(Obj&&)
        :default_ctor(true), move_ctor(true) { }

    bool default_ctor;
    bool move_ctor;
};

struct ConvertFromOptional {
    ConvertFromOptional()