Fix pattern bugs caught by new Roslyn diagnostic - #6012
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Add parentheses around negated disjunctive patterns so newer compilers do not report CS9336. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 7b2ca30d-742d-402c-8ba5-afec8b6d69a1
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Sep 8, 2026
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🟢 Approval recommended
The code changes are small, targeted, and correct; only a minor PR-description count mismatch was noted.
Pull request overview
This PR fixes incorrect C# negated-pattern logic exposed by a newer Roslyn diagnostic by adding parentheses so not applies to the full disjunctive pattern set, restoring the intended GC segment/generation filtering behavior in SOS extension commands.
Changes:
- Fix segment counting to exclude frozen/pinned segments by correctly negating the full
orpattern. - Fix ephemeral reference scanning to include Generation 1 objects by correctly negating the full
orpattern. - Fix fragmentation reporting to exclude large/pinned/frozen segments by correctly negating the full
orpattern.
File summaries
| File | Description |
|---|---|
| src/Microsoft.Diagnostics.ExtensionCommands/FindEphemeralReferencesToLOHCommand.cs | Corrects negated or patterns affecting segment counting and Gen0/Gen1 filtering. |
| src/Microsoft.Diagnostics.ExtensionCommands/DumpHeapService.cs | Corrects negated or pattern so pinned/frozen/large segments don’t contribute to fragmentation reporting. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 1
- Review effort level: Lite
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This was referenced Sep 9, 2026
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Summary
A newer Roslyn diagnostic exposed three existing negated-pattern bugs:
Parenthesizing each disjunctive pattern makes
notapply to the complete set of excluded values. This fixes the behavior and resolves the four CS9336 diagnostics.Testing
eng\build.ps1 -restore -build -ci -configuration Release -architecture x64 -privatebuildNote
This pull request description was generated with GitHub Copilot.