If an owner pointer already points to a valid memory buffer, it must not be assigned to another value without releasing its current resource first. Such assignment may lead to a resource leak even if the resource address is copied into some raw pointer (because raw pointers shouldn’t release resources). For more information, see the C++ Core Guidelines.

gsl::owner<Shape*> shape = nullptr;
while (shape = NextShape()) // C26405
    Process(shape) ? delete shape : 0;