.. title:: clang-tidy - bugprone-forward-declaration-namespace

bugprone-forward-declaration-namespace
======================================

Checks if an unused forward declaration is in a wrong namespace.

The check inspects all unused forward declarations and checks if there is any
declaration/definition with the same name existing, which could indicate that
the forward declaration is in a potentially wrong namespace.

.. code-block:: c++

  namespace na { struct A; }
  namespace nb { struct A {}; }
  nb::A a;
  // warning : no definition found for 'A', but a definition with the same name
  // 'A' found in another namespace 'nb::'

This check can only generate warnings, but it can't suggest a fix at this point.