id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12082	x3::forward_ast ambiguous call	mikhail.strelnikov@…	Joel de Guzman	"Following code works for boost::variant but fails for boost::spirit::x3::variant with '''error: call of '(const c) (boost::spirit::x3::forward_ast<s1>&)' is ambiguous'''


{{{
#define USE_SPIRIT_X3_VARIANT 1

#include <boost/fusion/include/define_struct_inline.hpp>
#include <boost/spirit/home/x3/support/ast/variant.hpp>
#include <boost/variant.hpp>

struct s1;

#if USE_SPIRIT_X3_VARIANT == 1
using s2 = boost::spirit::x3::variant<long, boost::spirit::x3::forward_ast<s1> >;
#else
using s2 = boost::variant<long, boost::recursive_wrapper<s1> >;
#endif

BOOST_FUSION_DEFINE_STRUCT_INLINE
(
    s1,
    (s2, v1)
)

BOOST_FUSION_DEFINE_STRUCT_INLINE
(
    magic,
    (int*, v1)
)

struct c
{
    int operator()(long) const { return 0; }
    int operator()(s1) const { return 1; }
    int operator()(magic) const { return 3; }
};

int main()
{
    s2 s; s = s1{};
    return boost::apply_visitor(c(), s);
}

}}}

[http://melpon.org/wandbox/permlink/BPdeuyNPLINriCr3]

As you can see, `magic` class does not belong to the variant, but still causes compilation error.
"	Bugs	closed	To Be Determined	spirit	Boost 1.60.0	Problem	wontfix