返回参考且仅参考

Question

I have the following function which is part of a Grid class:

T& select(unsigned int x, unsigned int y)
{
    return nodes[x + width * y].element;
}

Is there any way I can force the compiler to reject construction of a T from returned T& without deleting the copy constructor of T (which might not even be a class)?

auto n = grid.select(1,1); // this should be illegal

Answer 1

While you return a reference, what users of the code do with it later is entirely out of your control. The fact that they can use your reference to create a copy is valid in the language.