#include "../Eigen/Sparse"

using namespace Eigen;

#ifdef EIGEN_SHOULD_FAIL_TO_BUILD
void call_ref(Ref<SparseMatrix<float> > a) {}
#else
void call_ref(const Ref<const SparseMatrix<float> > &a) {}
#endif

int main() {
  SparseMatrix<float> a(10, 10);
  call_ref(a + a);
}