FSharMap.ComputeHashCode() throws OverflowException

[jmanty]

Hash function for F# map (ComputeHashCode) ends by taking the absolute value of the combined hash values of the map's contents. If the combined hash value is Int32.MinValue, getting the absolute value fails with System.OverflowException.

Repro steps

Run following code hash <| Map.add 1073740877 1 Map.empty

Expected behavior

A hash code is returned.

Actual behavior

System.OverflowException is thrown.

[syeerzy]

Hashcode could lower than zero, I don't think the abs operator is necessary.

[dsyme]

agreed