This one is on me, I think, in #10602. I wasn't aware this was legal: ```python >>> np.__version__ '1.13.3' >>> class Custom(np.void): pass >>> np.dtype(Custom) dtype('V') ``` ```python >>> np.__version__ '1.16.0.dev0+7af8e10' >>> class Custom(np.void): pass >>> np.dtype(Custom) RuntimeError: Internal error: NumPy dtype unrecognized type number ``` Not sure if this affects 1.15.0