boost::enable_if in 4.4.1 vs 4.1.2
Lewis Hyatt
The following code compiles with g++ 4.1.2 but does not compile with 4.4.1;
I get an error message saying the prototype does not match any declared in the
class. This happens both with Boost 1.40.0 and 1.33.1, on Debian (x86 64-bit).
Does anyone know what's up with this, is there some workaround? Thanks very much.
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_base_of.hpp>
#include <boost/type_traits/is_same.hpp>
template<typename T>
struct A {
struct B {};
template<typename U>
typename boost::enable_if_c<
boost::is_base_of<B, U>::value &&
!boost::is_same<B,U>::value>
::type f(U&);
};
template<typename T>
template<typename U>
typename boost::enable_if_c<
boost::is_base_of<typename A<T>::B, U>::value &&
!boost::is_same<typename A<T>::B, U>::value>
::type A<T>::f(U&) {}
int main() {
}
t.cpp:20: error: prototype for 'typename
boost::enable_if_c<(boost::is_base_of::value && (! boost::is_same::value)),
void>::type A<T>::f(U&)' does not match any in class 'A<T>'
t.cpp:12: error: candidate is: template<class T> template<class U> typename
boost::enable_if_c<(boost::is_base_of::value && (! boost::is_same::value)),
void>::type A::f(U&)
-Lewis