That was in reference to having 10s or 100s of members.

But you wrote it in reply to a description of 10s or 100s of lines of trivial members.

Maybe D doesn't have such a thing, as I said I don't plan to go look, but all the other languages I used as examples certainly do. Rust's Vec has almost 50 public associated functions, a few are non-trivial, but many are, and of course they take up hundreds of lines.

https://github.com/microsoft/STL/blob/main/stl/inc/vector is almost 4000 lines. As I said, C++ makes even a trivial function into a horrible mess like this:

    _CONSTEXPR20 void shrink_to_fit() { // reduce capacity to size, provide strong guarantee
        auto& _My_data         = _Mypair._Myval2;
        const pointer _Oldlast = _My_data._Mylast;
        if (_Oldlast != _My_data._Myend) { // something to do
            const pointer _Oldfirst = _My_data._Myfirst;
            if (_Oldfirst == _Oldlast) {
                _Tidy();
            } else {
                _Reallocate_exactly(static_cast<size_type>(_Oldlast - _Oldfirst));
            }
        }
    }