Fix cross-assembly source generation accessibility

[Amaury Levé (Evangelink)]

Summary

• make reflection-free member accessibility checks account for the declaring assembly
• prevent inaccessible nearer members from exposing hidden ancestor members during model construction
• add two-assembly regression coverage for inherited methods and properties

Testing

• build.cmd -test -projects test\UnitTests\MSTest.SourceGeneration.UnitTests\MSTest.SourceGeneration.UnitTests.csproj -bl

[github-actions]

🧵 Parallel-safety audit — PR #11014

Nothing audited here touches process-global state, shared filesystem paths, or
[ResourceLock] / [DoNotParallelize] declarations. The changed test method
(Generator_ExcludesInaccessibleMembersFromBaseTypeInAnotherAssembly) only builds
in-memory CSharpCompilation/GeneratorDriver objects, writes to a local
MemoryStream, and asserts on generated source text — no env vars, CWD, console
state, statics, or shared paths are involved. The two other changed files
(TestClassModelBuilder.cs, TestMemberValidationHelper.cs) are pure analyzer/
source-generator logic with no test-time side effects. The [assembly: Parallelize(...)]
occurrences elsewhere in this file are inside raw source-code strings used as
generator input for other, unrelated tests — not real attributes on the test
assembly — so they do not change this project's parallelization state.

MSTest.SourceGeneration.UnitTests carries no [assembly: Parallelize] /
[assembly: DoNotParallelize], no .runsettings, and no testconfig.json, so
its effective scope is MSTest's default: off. Nothing to flag for
parallel-safety.

Audited MSTest.SourceGeneration.UnitTests at scope off, workers n/a.

_{Re-run with /parallel-audit.}

🤖 Automated content by GitHub Copilot. Generated by the Parallel-safety audit on PR (on open / sync) workflow. · auto · 40.9 AIC · ⌖ 4.42 AIC · ⊞ 24.8K · [◷]( · ◷)

[github-actions]

🧪 Expert test review — PR #11014

Grade	Test	Mutation	Notes	How to improve
A (90–100)	new MSTestReflectionMetadataGeneratorTests. Generator_ ExcludesInaccessibleMembersFromBaseTypeInAnotherAssembly	4/4 killed	Covers the derived-first dedup regression: an inaccessible derived-type member correctly shadows and excludes an otherwise-accessible grandparent member, plus verifies the inaccessible-getter diagnostic and absence of compile errors.	—

_{This advisory comment was generated automatically. Grades are heuristic
and informational — they do not block merging. Suggestions on the Files
changed tab can be applied with one click. Re-run with
/review-tests.}

🤖 Automated content by GitHub Copilot. Generated by the Test Reviewer on PR (on open / sync) workflow. · auto · 43.1 AIC · ⌖ 2.47 AIC · ⊞ 16.9K · [◷]( · ◷)

[github-actions]

Note

🤖 Automated review by GitHub Copilot. Generated by the Expert Code Review workflow. To request a follow-up action, reply by tagging @copilot directly.

✅ 22/22 dimensions clean — no findings.

Review notes:

• Algorithmic Correctness: Moving the dedup check (seenMethodKeys.Add) before the accessibility check is correct — derived-first iteration means the derived declaration wins for new-shadowed members. The hasUnsupportedTestMethod flag is still set on the first (derived) occurrence when applicable. For properties, the flag is set unconditionally before dedup/accessibility, so no regression there either.
• The core fix (IsAccessibleFromConsumer now taking consumingAssembly) correctly addresses the bug where Internal and ProtectedOrInternal members from external assemblies were incorrectly treated as accessible. The delegation to SymbolReferenceabilityHelper.IsMemberAccessibleFrom is consistent with how DynamicDataSourceBuilder and AttributeMaterializationHelper already handle this.
• HasGettableValue now uses the same assembly-aware check via IsMemberAccessibleFrom(getter.DeclaredAccessibility, getter.ContainingType, consumingAssembly), replacing the hardcoded accessibility enum check — consistent and correct.
• Dictionary→HashSet refactor reduces memory by not storing values that were never read back, while preserving the same dedup semantics.
• Test coverage: The new Generator_ExcludesInaccessibleMembersFromBaseTypeInAnotherAssembly test exercises the cross-assembly scenario with multi-level inheritance, new-shadowing, protected internal inaccessibility, and inaccessible getters — good coverage of the fix.

[Copilot]

Copilot review overview

🟡 Changes recommended

Two critical hiding defects remain, and cross-assembly internal coverage is incomplete.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review tier: Balanced
Findings: 2 · 1

New issues introduced by this change (3)

Severity	Finding
	src/​Analyzers/​MSTest.SourceGeneration/​Generators/​TestClassModelBuilder.cs — These kind-specific sets still miss cross-kind hiding. C# member lookup hides base members by name…
	src/​Analyzers/​MSTest.SourceGeneration/​Generators/​TestClassModelBuilder.cs — BuildMethodSignatureKey distinguishes static and instance methods, but staticness is not part of…
	src/​Analyzers/​MSTest.SourceGeneration/​Generators/​TestMemberValidationHelper.cs — The assembly-sensitive predicate now covers both Internal and ProtectedOrInternal, but the…

What changed in this PR

Updates source generation to account for cross-assembly accessibility and inherited-member hiding.

Changes:

• Adds assembly-aware accessibility checks.
• Revises inherited-member filtering.
• Adds two-assembly regression coverage.

File	Review
test/​UnitTests/​MSTest.SourceGeneration.UnitTests/​MSTestReflectionMetadataGeneratorTests.cs	Adds cross-assembly tests, but lacks direct internal member coverage.
src/​Analyzers/​MSTest.SourceGeneration/​Generators/​TestMemberValidationHelper.cs	Adds assembly-sensitive checks. Moderate: add cross-assembly internal method, property, and getter regressions.
src/​Analyzers/​MSTest.SourceGeneration/​Generators/​TestClassModelBuilder.cs	Critical: method hiding incorrectly distinguishes staticness and does not account for cross-kind hiding, potentially generating uncompilable code.

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