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dotnet / runtime Public

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Optimize HashSet.UnionWith to copy data from another HashSet when empty#122952

Merged

stephentoub merged 4 commits intomaindotnet/runtime:mainfrom

copilot/fix-unionwith-copy-datadotnet/runtime:copilot/fix-unionwith-copy-dataCopy head branch name to clipboard

Jan 12, 2026

Conversation Commits4 (4)Checks Files changed

Merged

Optimize HashSet.UnionWith to copy data from another HashSet when empty#122952
stephentoub merged 4 commits intomainfrom
copilot/fix-unionwith-copy-data

Commits

Commits on Jan 7, 2026

Initial plan
Copilot
committed
Optimize HashSet.UnionWith for empty sets with compatible HashSet source and add tests

Copilot
and
stephentoub
committed
Consolidate UnionWith tests into single parameterized test

Copilot
and
stephentoub
committed
Refactor UnionWith test to use MemberData with foreach loops

Copilot
and
stephentoub
committed

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