Move diagnostic generation from LibraryImportGenerator to LibraryImportDiagnosticsAnalyzer

[Copilot]

Summary

Continuing to address review feedback from @jkoritzinsky.

Changes Made

1. Updated CompilationExtensions.GetEnvironmentFlags - Checks for DisableRuntimeMarshallingAttribute on the source assembly instead of the module

2. Removed Diagnostics field from IncrementalStubGenerationContext - Generator no longer collects or returns diagnostics

3. Fixed AddDisableRuntimeMarshallingAttributeFixerTests - Updated to use LibraryImportDiagnosticsAnalyzer instead of EmptyDiagnosticAnalyzer

Test Status

• 674/703 tests pass (28 still failing)
• Remaining failures are in:
  • CompileFails.ValidateSnippets tests
  • ByValueContentsMarshalling.VerifyByValueMarshallingAttributeUsageInfoMessages tests

Investigation Notes

The failing tests run both generator and analyzer together via CSharpSourceGeneratorVerifier. The analyzer returns 0 diagnostics when it should report SYSLIB1051/SYSLIB1052/SYSLIB1092 diagnostics.

Possible causes being investigated:

1. The analyzer's RegisterSymbolAction may not be triggering for methods with compile errors
2. The GeneratedCodeAnalysisFlags.None setting may be affecting when the analyzer runs
3. There may be a timing issue where the analyzer runs before/after the generator

This requires further investigation to understand why the analyzer doesn't report diagnostics in these specific test scenarios.

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Mis-clicked approve

[jkoritzinsky]

@copilot address this review.

[jkoritzinsky]

@copilot please address the feedback in this review.

[jkoritzinsky]

@copilot Please adjust CompilationExtensions.GetEnvironmentFlags to check for DisableRuntimeMarshallingAttribute on the source assembly instead of the module. Also, add handling for the rest of the diagnostic edge cases for the remaining 5% of tests. Then, please remove the Diagnostics field from LibraryImportGenerator.IncrementalStubGenerationContext and remove downstream usages.

[Copilot]

@copilot Please adjust CompilationExtensions.GetEnvironmentFlags to check for DisableRuntimeMarshallingAttribute on the source assembly instead of the module. Also, add handling for the rest of the di...

Addressed in commits f33ac74 and 9f85c66:

1. CompilationExtensions.GetEnvironmentFlags - Updated to check compilation.Assembly.GetAttributes() instead of compilation.SourceModule.GetAttributes() for DisableRuntimeMarshallingAttribute.

2. Removed Diagnostics field - Removed from IncrementalStubGenerationContext record and updated all downstream usages. The generator now uses discarding diagnostics bags and no longer returns diagnostics.

3. Diagnostic edge cases - Fixed AddDisableRuntimeMarshallingAttributeFixerTests to use LibraryImportDiagnosticsAnalyzer. 28 tests still fail - the analyzer isn't reporting diagnostics for CompileFails.ValidateSnippets tests when run together with the generator. This appears to be related to how the analyzer's RegisterSymbolAction interacts with methods that have compile errors. Investigating further.