id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
11422	is_base<T, T> is broken on MSVC10 when T is not defined	Aleksej Lebedev <root@…>	John Maddock	"Currently on Windows with MSVC10 boost defines BOOST_IS_BASE_OF (which is used in is_base_and_derived, which is used in is_base_of) as follows:

{{{
#define BOOST_IS_BASE_OF(T,U) (__is_base_of(T,U) && !is_same<T,U>::value)
}}}

But microsoft's intrinsic {{{__is_base_of}}} cannot be used with the same type (i.e. T = U) when it (the type) is not defined.

When the following is compiled
{{{
class A;
typedef typename boost::is_base_of<A, A>::type x;
}}}

you get an error message:
{{{
...\include\boost\type_traits\is_base_and_derived.hpp(228) : error C2139: 'A' : an undefined class is not allowed as an argument to compiler intrinsic type trait '__is_base_of'
...\include\boost\type_traits\is_base_of.hpp(29) : see reference to class template instantiation 'boost::detail::is_base_and_derived_impl<B,D>' being compiled
        with
        [
            B=A,
            D=A
        ]
}}}

The same code compiles on gcc-4.8.2 and clang-3.6."	Bugs	closed	To Be Determined	type_traits	Boost 1.57.0	Problem	duplicate