Description

This fixes the hashCode calculation for KeySet<T> so that it doesn't depend on the insertion order of the keys in the set.

The fix involves switching from Set<T> to HashSet<T> internally, so that the iteration order is stable around the hash values of the inserted keys, and not the insertion order. This matters when hashList is called in KeySet<T>.hashCode to build the hash value of the contents of the internal set.

Related Issues

#38919

Tests

• Modified the "LogicalKeySet works as a map key." test to include tests for the hashCode calculation both from the up-to-four key constructor, and the fromSet constructor.

Checklist

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Breaking Change

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• No, this is not a breaking change.