cppcoreguidelines-missing-std-forward

Warns when a forwarding reference parameter is not forwarded inside the function body.

Example:

template <class T>
void wrapper(T&& t) {
  impl(std::forward<T>(t), 1, 2); // Correct
}

template <class T>
void wrapper2(T&& t) {
  impl(t, 1, 2); // Oops - should use std::forward<T>(t)
}

template <class T>
void wrapper3(T&& t) {
  impl(std::move(t), 1, 2); // Also buggy - should use std::forward<T>(t)
}

template <class F>
void wrapper_function(F&& f) {
  std::forward<F>(f)(1, 2); // Correct
}

template <class F>
void wrapper_function2(F&& f) {
  f(1, 2); // Incorrect - may not invoke the desired qualified function operator
}

This check implements F.19 from the C++ Core Guidelines.