Solution
Here is the solution to the problem in the previous lesson.
We'll cover the following...
We'll cover the following...
Explanation
Add this line to class S:
void foo(const T&& t) = delete;
foo(T&& t) only prohibits non-const rvalues. It allows const rvalues. By deleting the implementation of foo(const T&& t), we make sure that no rvalues are accepted.