Fix dataflow analysis of lambdas in async methods#122623
Merged
MichalStrehovsky merged 2 commits intodotnet:mainfrom Dec 22, 2025
Merged
Fix dataflow analysis of lambdas in async methods#122623MichalStrehovsky merged 2 commits intodotnet:mainfrom
MichalStrehovsky merged 2 commits intodotnet:mainfrom
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To the same tune as dotnet#122450. This is a bug farm, as expected, but likely still better than trying to teach the code that is shared with ILLink and Roslyn analyzer about async variants.
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Pull request overview
This PR fixes a bug in dataflow analysis where lambdas and local functions within async methods were not being properly analyzed. The fix unwraps AsyncMethodVariant instances to their target methods before performing compiler-generated member analysis, following the same pattern used elsewhere in the codebase for handling async variants.
Key Changes
- Added logic to unwrap
AsyncMethodVariantto its target method in the dataflow analysis path - Added test coverage for async methods containing local async methods with dataflow warnings
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/Dataflow/CompilerGeneratedState.cs | Added AsyncMethodVariant unwrapping logic in TryGetUserMethodForCompilerGeneratedMember to properly resolve user methods for compiler-generated members in async contexts |
| src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/RuntimeAsyncMethods.cs | Added test case RuntimeAsyncWithAwaitedLocalMethod to verify dataflow warnings are correctly emitted for local async methods, and added System.Reflection using directive |
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jtschuster
approved these changes
Dec 18, 2025
This was referenced Jan 9, 2026
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To the same tune as #122450. This is a bug farm, as expected, but likely still better than trying to teach the code that is shared with ILLink and Roslyn analyzer about async variants.
Cc @dotnet/ilc-contrib