Hi, I ran into a scenario where enable_if worked, but not enable_if_c, using MSVC 8.0.50727.762 (SP.050727-7600). // simple classes to test enable_if_c template< class Type, class Enabler = void> struct BaseC { static bool const value = false; }; template<class Type> struct BaseC< Type, typename enable_if_c<is_integral<Type>::value >::type> { static bool const value = true; }; template<class Type> struct DerivedC : BaseC<Type> {}; // actual tests void test_c() { BOOST_STATIC_ASSERT(BaseC<short>::value == true); // fine BOOST_STATIC_ASSERT(DerivedC<short>::value == true); // fine BOOST_STATIC_ASSERT(DerivedC<int>::value == true); // fails here BOOST_STATIC_ASSERT(BaseC<int>::value == true); // fails here } As you've probably noticed, it only fails if DerivedC got instantiated before BaseC, with the same integral template argument. Am I doing anything wrong here or is this a compiler bug? Source code available here: http://fsfoundry.org/tmp/test_enable_if.cpp VC8 solution available here: http://fsfoundry.org/tmp/test_enable_if.zip Compiles on g++ 4.1.2 with Boost 1.33.1 Fails on VC8 with Boost 1.34.1 and 1.33.0 Regards, ken