Example:

```
#include <Eigen/Dense>

void test()
{
        auto const M = 0;   // If changed to M = 1, works fine
	auto const N1 = 2;
	auto const N2 = 1;

	Eigen::Matrix<double, M, N1> A1;
	Eigen::Matrix<double, M, N2> A2;
	Eigen::Matrix<double, M, N1 + N2> B;

	B << A1, A2;
}
```

Produces the following error at runtime:

```
/usr/local/include/eigen3/Eigen/src/Core/CommaInitializer.h:114: Eigen::CommaInitializer<MatrixType>::~CommaInitializer() [with XprType = Eigen::Matrix<double, 0, 3>]: Assertion `(m_row+m_currentBlockRows) == m_xpr.rows() && m_col == m_xpr.cols() && "Too few coefficients passed to comma initializer (operator<<)"' failed.
```