The conda-forge build caught the following error: conda-forge/scikit-learn-feedstock#259 (comment)

It boils down to the function missing the long long fused type. However, I'm not sure that our current CI would have caught the issue at any point since we would need a Windows with the latest pip version (here this is even with --pre since NumPy is not released yet).

We should have this fix included in 1.5 final release.