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. ```
ouch, that's a truly nasty corner case! Fixed: default: https://bitbucket.org/eigen/eigen/commits/30293148a638/ 3.2: https://bitbucket.org/eigen/eigen/commits/44abf0a7b16a/