C++ compile fail when using Visual Studio and setting WITH_CUDA=ON

The error is like csrc\cuda\segment_coo_cuda.cu(217): error C2975: 'REDUCE': invalid template argument for 'Reducer', expected compile-time constant expression, etc. 

It seems that adding "static constexpr" in reducer.cuh can solve the problem, like https://github.com/rusty1s/pytorch_scatter/pull/342, can it be merged? Thanks!