Example:

wtf/text/StringConcatenate.h:

    namespace WTF {  // <- ***** namespace here
    
    template<typename StringType>
    class StringTypeAdapter {
        DISALLOW_NEW();
    };
    
    template<>
    class StringTypeAdapter<char*> {
    ...
    public:
    ...
        // ***** We will rewrite |writeTo| to |WriteTo| below
        //       (since we are in WTF namespace).
        void writeTo(LChar* destination);
    ...
    };

wtf/text/StringConcatenate.cpp:

    // ***** no |namespace WTF {| here
    // but obviously method definition below is for WTF namespace
    // (because of the explicit nested name qualifier).

    ...
    // ***** BUG: need to rewrite |writeTo| to |WriteTo|
    //       (rewrite doesn't happen because there is no namespace node
    //        inside StringConcatenate.cpp)
    void WTF::StringTypeAdapter<char*>::writeTo(LChar* destination)
    {
        for (unsigned i = 0; i < m_length; ++i)
            destination[i] = static_cast<LChar>(m_buffer[i]);
    }
    ...