C++ code - 5 lines

Link:

C++, pasted on Apr 25:

#include <boost/shared_ptr.hpp>
using boost::shared_ptr;
struct Hoge;
void funcRef(shared_ptr<Hoge>& ref = shared_ptr<Hoge>()) {}
int main() {}

Output:

1 2	Line 4: error: default argument for 'boost::shared_ptr<Hoge>& ref' has type 'boost::shared_ptr<Hoge>' compilation terminated due to -Wfatal-errors.