The C++ core guideline support library has it. https://github.com/microsoft/GSL/blob/main/docs/headers.md#user-content-H-pointers-not_null https://github.com/m

The C++ core guideline support library has it. https://github.com/microsoft/GSL/blob/main/docs/headers.md#user-content-H-pointers-not_null https://github.com/microsoft/GSL/blob/main/docs/headers.md#u... What do you mean by move-out unique_ptr? That the not_null ptr type would ne null after it's been moved? In that case that's just a plain usage error, same as how you could memset it to null.