Cast from UInt64 to Int could be problematic on macOS

[cduvenhorst]

https://github.com/valhalla/valhalla/blob/5b3cd9704ffd699b992b08bc4a5bf60e34d318f5/src/tyr/serializers.cc#L442

num_lanes_blocked is defined as UInt64, writer writes Int. This gives an compiler error on default build configuration.

[kevinkreiser]

it likely depends on your platform and compiler, as you can see our builds complete without issue. in practice, its highly unlikely that this matters. no roads that i know about have more than 2^31 lanes, so the number wouldnt wrap around on the signed integer conversion. that said, you are right that we should fix it. it looks like there are a number of places where we just use Int without looking at the sign :frowning_face: do you have time to submit a pr?

[namanvats]

@kevinkreiser If it's open, can I pick this issue ?

[nilsnolde]

feel free:)