.. title:: clang-tidy - cppcoreguidelines-missing-std-forward

cppcoreguidelines-missing-std-forward
=====================================

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

Example:

.. code-block:: c++

  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
  }

Options
-------

.. option:: ForwardFunction

   Specify the function used for forwarding. Default is `::std::forward`.

This check implements `F.19
<http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#rf-forward>`_
from the C++ Core Guidelines.

Limitations
-----------

Explicit object parameters (``this Self&&``) with a type constraint are not
checked to avoid false positives. Such parameters are rarely intended to be
perfectly forwarded.
