The following clears the unexpected failure for optional on borland-5.6.4 Index: optional.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/optional/optional.hpp,v retrieving revision 1.1 diff -w -u -r1.1 optional.hpp --- optional.hpp 7 Jul 2004 15:10:03 -0000 1.1 +++ optional.hpp 16 Jul 2004 13:11:36 -0000 @@ -347,7 +347,7 @@ reference_const_type dereference( internal_type const* p, is_reference_tag ) const { return p->get() ; } reference_type dereference( internal_type* p, is_reference_tag ) { return p->get() ; } - void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; } + void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->internal_type::~internal_type() ; m_initialized = false ; } void destroy_impl ( is_reference_tag ) { m_initialized = false ; } // If T is of reference type, trying to get a pointer to the held value must result in a compile-time error.