invalid usage of std::list in match_results

[Andrey Semashev]

I use MSVC 9 with STLport 5.2.1. When compiling the following code snippet:

#include <string>
#include <boost/xpressive/xpressive_dynamic.hpp>

namespace xpressive = boost::xpressive;

int main(int, char*[])
{
    typedef xpressive::basic_regex< std::string::const_iterator > regex_t;
    regex_t rex = regex_t::compile(std::string("abc"), regex_t::ECMAScript | regex_t::optimize);

    return 0;
}

I get the following error:

xpressive.cpp
../STLPort/stlport\stl/type_traits.h(249) : error C2139: 'boost::xpressive::match_results<BidiIter>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__has_trivial_constructor'
        with
        [
            BidiIter=const char *
        ]
        ../STLPort/stlport\stl/pointers/_tools.h(76) : see reference to class template instantiation 'stlp_std::__type_traits<_Tp>' being compiled
        with
        [
            _Tp=boost::xpressive::match_results<const char *>
        ]
        ../STLPort/stlport\stl/pointers/_list.h(61) : see reference to class template instantiation 'stlp_std::priv::_StorageType<_Tp>' being compiled
        with
        [
            _Tp=boost::xpressive::match_results<const char *>
        ]
        .\boost/xpressive/detail/core/results_cache.hpp(43) : see reference to class template instantiation 'stlp_std::list<_Tp>' being compiled
        with
        [
            _Tp=boost::xpressive::match_results<const char *>
        ]
        .\boost/xpressive/match_results.hpp(1341) : see reference to class template instantiation 'boost::xpressive::detail::nested_results<BidiIter>' being compiled
        with
        [
            BidiIter=const char *
        ]
        .\boost/xpressive/detail/core/state.hpp(239) : see reference to class template instantiation 'boost::xpressive::match_results<BidiIter>' being compiled
        with
        [
            BidiIter=const char *
        ]
        .\boost/xpressive/detail/core/state.hpp(235) : while compiling class template member function 'void boost::xpressive::detail::match_state<BidiIter>::swap_context(boost::xpressive::detail::match_context<BidiIter> &)'
        with
        [
            BidiIter=const char *
        ]
        .\boost/xpressive/detail/core/matcher/end_matcher.hpp(35) : see reference to class template instantiation 'boost::xpressive::detail::match_state<BidiIter>' being compiled
        with
        [
            BidiIter=const char *
        ]
        .\boost/xpressive/detail/dynamic/dynamic.hpp(80) : see reference to function template instantiation 'bool boost::xpressive::detail::end_matcher::match<BidiIter,const T>(boost::xpressive::detail::match_state<BidiIter> &,const Next &)' being compiled
        with
        [
            BidiIter=const char *,
            T=const boost::xpressive::detail::matchable_ex<const char *>,
            Next=const boost::xpressive::detail::matchable_ex<const char *>
        ]
        .\boost/xpressive/detail/dynamic/dynamic.hpp(79) : while compiling class template member function 'bool boost::xpressive::detail::dynamic_xpression<Matcher,BidiIter>::match(boost::xpressive::detail::match_state<BidiIter> &) const'
        with
        [
            Matcher=boost::xpressive::detail::end_matcher,
            BidiIter=const char *
        ]
        .\boost/xpressive/detail/dynamic/dynamic.hpp(164) : see reference to class template instantiation 'boost::xpressive::detail::dynamic_xpression<Matcher,BidiIter>' being compiled
        with
        [
            Matcher=boost::xpressive::detail::end_matcher,
            BidiIter=const char *
        ]
        .\boost/xpressive/regex_compiler.hpp(216) : see reference to function template instantiation 'boost::xpressive::detail::sequence<BidiIter> boost::xpressive::detail::make_dynamic<BidiIter,boost::xpressive::detail::end_matcher>(const Matcher &)' being compiled
        with
        [
            BidiIter=const char *,
            Matcher=boost::xpressive::detail::end_matcher
        ]
        .\boost/xpressive/regex_compiler.hpp(120) : see reference to function template instantiation 'boost::xpressive::basic_regex<BidiIter> boost::xpressive::regex_compiler<BidiIter>::compile_<InputIter>(FwdIter,FwdIter,boost::xpressive::regex_compiler<BidiIter>::flag_type,stlp_std::forward_iterator_tag)' being compiled
        with
        [
            BidiIter=const char *,
            InputIter=const char *,
            FwdIter=const char *
        ]
        .\boost/xpressive/regex_compiler.hpp(129) : see reference to function template instantiation 'boost::xpressive::basic_regex<BidiIter> boost::xpressive::regex_compiler<BidiIter>::compile<const char*>(InputIter,InputIter,boost::xpressive::regex_compiler<BidiIter>::flag_type)' being compiled
        with
        [
            BidiIter=const char *,
            InputIter=const char *
        ]
        .\boost/xpressive/basic_regex.hpp(191) : see reference to function template instantiation 'boost::xpressive::basic_regex<BidiIter> boost::xpressive::regex_compiler<BidiIter>::compile<InputRange>(const InputRange &,boost::xpressive::regex_compiler<BidiIter>::flag_type)' being compiled
        with
        [
            BidiIter=const char *,
            InputRange=stlp_std::basic_string<char,stlp_std::char_traits<char>,stlp_std::allocator<char>>
        ]
        xpressive.cpp(9) : see reference to function template instantiation 'boost::xpressive::basic_regex<BidiIter> boost::xpressive::basic_regex<BidiIter>::compile<stlp_std::basic_string<_CharT,_Traits,_Alloc>>(const InputRange &,boost::xpressive::basic_regex<BidiIter>::flag_type)' being compiled
        with
        [
            BidiIter=const char *,
            _CharT=char,
            _Traits=stlp_std::char_traits<char>,
            _Alloc=stlp_std::allocator<char>,
            InputRange=stlp_std::basic_string<char,stlp_std::char_traits<char>,stlp_std::allocator<char>>
        ]
../STLPort/stlport\stl/type_traits.h(250) : error C2139: 'boost::xpressive::match_results<BidiIter>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__has_trivial_copy'
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/type_traits.h(251) : error C2139: 'boost::xpressive::match_results<BidiIter>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__has_trivial_assign'
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/type_traits.h(252) : error C2139: 'boost::xpressive::match_results<BidiIter>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__has_trivial_destructor'
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/type_traits.h(253) : error C2139: 'boost::xpressive::match_results<BidiIter>' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_pod'
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/pointers/_tools.h(79) : error C2027: use of undefined type 'boost::xpressive::match_results<BidiIter>'
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/pointers/_tools.h(79) : error C2227: left of '->{dtor}' must point to class/struct/union/generic type
        type is 'boost::xpressive::detail::match_state<BidiIter> *const '
        with
        [
            BidiIter=const char *
        ]
../STLPort/stlport\stl/pointers/_tools.h(79) : fatal error C1903: unable to recover from previous error(s); stopping compilation

I assume the problem is that nested_results< BidiIter > template derives from std::list< match_results< BidiIter > >, but at this point match_results is not complete because the nested_results template is instantiated by match_results< BidiIter >::nested_results_ member variable. The Standard forbids to instantiate STL containers on incomplete types, so I guess, STLport has no issue here.

Just in case you try to reproduce, I have these macros defined: _STLP_USE_TEMPLATE_EXPRESSION=1, _STLP_USE_PTR_SPECIALIZATIONS=1.

[Eric Niebler]

(In [57174]) nested results uses a custom list type that allows incomplete types, does no dynamic allocation in the default constructor, and has a guarnteed O(1) splice; fixes #3278