fix-analyzer-bug

# Fix Analyzer Bug ## Overview Reproduce in an existing test file, minimal code fix, changelog entry. Highest-frequency contributor task. ## When to Use - Analyzer reports when it should not (false positive) - Analyzer misses case it should report (false negative) - Code fix produces wrong transformation - Issue title includes `RCS####`, `RR####`, `CS####`, or `RCF####` **Not for:** new rules (`add-analyzer`, `add-refactoring`, `add-compiler-diagnostic-fix`), deprecation (`deprecate-analyzer-or-refactoring`). For test patterns use in-repo verifiers — not public NuGet testing docs. ## Quick Reference | Prefix | Code | Tests | Verifier | |--------|------|-------|----------| | RCS1 | `Analyzers/CSharp/Analysis/` | `Tests/Analyzers.Tests/` | `AbstractCSharpDiagnosticVerifier` | | RCS0 | `Formatting.Analyzers/CSharp/` | `Tests/Formatting.Analyzers.Tests/` | `AbstractCSharpDiagnosticVerifier` | | RCS9 | `CodeAnalysis.Analyzers/CSharp/` | `Tests/CodeAnalysis.Analyzers.Tests/` | `AbstractCSharpDiagnosticVerifier` | | RR | `Refactorings/CSharp/Refactorings/` | `Tests/Refactorings.Tests/` | `AbstractCSharpRefactoringVerifier` | | CS / RCF | `CodeFixes/CSharp/CodeFixes/` | `Tests/CodeFixes.Tests/` | `AbstractCSharpCompilerDiagnosticFixVerifier` | Search `DiagnosticIdentifiers.X` / `DiagnosticRules.X` / `CompilerDiagnosticIdentifiers.*` in generated files. Roslynator analyzer code fixes live in matching `.CodeFixes` projects. ## Implementation Add `[Fact]` to existing `*Tests.cs` — new file only if none exists. | Case | Method | |------|--------| | False positive | `VerifyNoDiagnosticAsync` | | False negative | `VerifyDiagnosticAsync` with `[|...|]` | | Analyzer/refactoring fix regression | `VerifyDiagnosticAndFixAsync` | | Compiler fix regression | `VerifyFixAsync` (no `[|...|]` markers) | Config-dependent: `options: Options.AddConfigOption(...)`. Verify (adjust project and filter): ```bash cd src && dotnet build Roslynator.sln cd src && dotnet test Tests/Analyzers.Tests --no-build --filter "FullyQualifiedName~RCS####" cd src && dotnet test Tests/CodeFixes.Tests --no-build --filter "FullyQualifiedName~CS####" cd src && dotnet format Roslynator.sln --no-restore --verify-no-changes --severity info ``` Changelog examples: [references/changelog-examples.md](references/changelog-examples.md). ## Pull request When the fix targets a GitHub issue, the PR body **must** include a closing keyword on its own line (same pattern as recent analyzer fix PRs): ```markdown Fixes #NNNN ``` Use `Fixes #NNNN` or `Closes #NNNN`. A markdown link such as `[#1812](https://github.com/dotnet/roslynator/issues/1812)` does **not** create a GitHub issue reference and will not auto-close the issue. In `CHANGELOG.md`, end the entry with `([PR](https://github.com/dotnet/roslynator/pull/NNNN))` (see [references/changelog-examples.md](references/changelog-examples.md)). Do not use an issue link there. Place `Fixes #NNNN` after the Summary bullets and before the Test plan, for example: ```markdown ## Summary - … Fixes #1812 ## Test plan - … ``` ## Common Mistakes | Mistake | Fix | |---------|-----| | Copy test pattern from `analyzers-testing.md` | In-repo `AbstractCSharpDiagnosticVerifier` + `DiagnosticRules.X` | | Copy from `compiler-diagnostic-fixes-testing.md` | In-repo `AbstractCSharpCompilerDiagnosticFixVerifier` + `CompilerDiagnosticIdentifiers.*` | | New test file per case | Extend existing `RCS####...Tests.cs` or `CS####...Tests.cs` | | Change `Analyzers.xml` for logic bugs | Metadata only for docs/severity defaults | | `[|...|]` in compiler fix tests | Compiler diagnostic location is implicit | | Full test suite | Filter by rule id is enough | | Skip test | CONTRIBUTING.md requires tests for bug fixes | | Changelog ends with issue link (`[#NNNN](.../issues/...)`) | End with `([PR](https://github.com/dotnet/roslynator/pull/NNNN))` | | Markdown-only issue link in PR body | Use `Fixes #NNNN` so GitHub links and auto-closes the issue |