http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51336
Bug #: 51336 Summary: [C++11] is_abstract and sfinae Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: marc.gli...@normalesup.org #include <type_traits> template<class T> struct A { template<class=typename std::enable_if<std::is_same<T,int>::value>::type> A(A const&){} }; constexpr bool b = std::is_abstract<A<double>>::value; $ g++ -std=c++0x n.cc -c n.cc: In instantiation of 'struct A<double>': /tmp/gcc/inst/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/../../../../include/c++/4.7.0/type_traits:530:12: required from 'struct std::is_abstract<A<double> >' n.cc:7:47: required from here n.cc:5:3: error: no type named 'type' in 'struct std::enable_if<false, void>' I am not sure what is supposed to happen (that's why I tried), but this result doesn't seem right. Filed under C++ because is_abstract directly forwards to the __is_abstract builtin, but feel free to reassign to libstdc++ if you think the problem is there somehow. I first tried it with is_copy_constructible (which indirectly calls is_abstract through is_destructible) to check the value it would give (clang+libc++ says is_copy_constructible is true).