Oreo  |  8.0.0_r4
C++程序  |  14行  |  210 B 

#include "../Eigen/Core"

using namespace Eigen;

int main()
{
  VectorXf a(10), b(10);
  VectorXf const &ac(a);
#ifdef EIGEN_SHOULD_FAIL_TO_BUILD
  b.swap(ac);
#else
  b.swap(ac.const_cast_derived());
#endif
}