Function destroy_impl

boost/optional/optional.hpp:477–477

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581))
    void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->internal_type::~internal_type() ; m_initialized = false ; }
#else
    void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; }
#endif