Give a container value semantics

Reason

Regular objects are simpler to think and reason about than irregular ones. Familiarity.

Note

If meaningful, make a container Regular (the concept). In particular, ensure that an object compares equal to its copy.

Example

void f(const Sorted_vector<string>& v)
{
    Sorted_vector<string> v2 {v};
    if (v != v2)
        cout << "Behavior against reason and logic.\n";
    // ...
}

Enforcement

???