Propagate DynamicallyAccessedMembers annotations to auto-properties only #119329
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…ferences to find backing field
…erties with CompilerGenerated accessors
jtschuster
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Pull Request Overview
This PR refines the heuristics for propagating DynamicallyAccessedMembers annotations to backing fields in the trimmer and ILC tools. The change ensures that only fully auto-generated properties (where all accessors and backing fields have CompilerGeneratedAttribute) receive automatic annotation propagation, addressing compatibility issues with C# 14's field keyword and semi-auto properties.
Key changes:
- Tightened property backing field detection heuristics to check
CompilerGeneratedAttributeon all accessors - Added comprehensive test coverage for the
fieldkeyword functionality - Updated test infrastructure to use C# Preview language version to support new features
Reviewed Changes
Copilot reviewed 10 out of 11 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| PropertyDataFlow.cs | Added CompilerGeneratedAttribute to test accessors and new test class for unrecognized field scenarios |
| FieldKeyword.cs | New comprehensive test file covering field keyword functionality with various property patterns |
| FlowAnnotations.cs (linker) | Refactored backing field detection logic to use IsFullyAutoProperty check and improved error handling |
| FlowAnnotations.cs (ILC) | Parallel implementation of the refined heuristics for ILC compiler |
| MethodDefinitionExtensions.cs | Added IsCompilerGenerated extension method for checking compiler-generated attributes |
| Test infrastructure files | Updated to use C# Preview language version for field keyword support |
src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/PropertyDataFlow.cs
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src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/Dataflow/FlowAnnotations.cs
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src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/Dataflow/FlowAnnotations.cs
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Simplifies checks for if we need to warn because we were unable to find a backing field. Adds a test case for when there is a single auto-prop accessor and it could not find the backing field.
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/backport to release/10.0 |
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Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/17501553287 |
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@jtschuster backporting to "release/10.0" failed, the patch most likely resulted in conflicts: $ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch
Applying: Add more issue links for ExpectedWarnings that don't match
Using index info to reconstruct a base tree...
M src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeDataflow.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExceptionalDataFlow.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExponentialDataFlow.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/FeatureGuardAttributeDataFlow.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsFromXML.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInAssembly.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInCompilerGeneratedCode.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypes.cs
M src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypesUsingTarget.cs
Falling back to patching base and 3-way merge...
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeDataflow.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/CompilerGeneratedCodeDataflow.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExceptionalDataFlow.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExceptionalDataFlow.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExponentialDataFlow.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/ExponentialDataFlow.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/FeatureGuardAttributeDataFlow.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/DataFlow/FeatureGuardAttributeDataFlow.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsFromXML.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsFromXML.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInAssembly.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInAssembly.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInCompilerGeneratedCode.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInCompilerGeneratedCode.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypes.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypes.cs
Auto-merging src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypesUsingTarget.cs
CONFLICT (content): Merge conflict in src/tools/illink/test/Mono.Linker.Tests.Cases/Warnings/WarningSuppression/DetectRedundantSuppressionsInMembersAndTypesUsingTarget.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 Add more issue links for ExpectedWarnings that don't match
Error: The process '/usr/bin/git' failed with exit code 128Please backport manually! |
jtschuster
added a commit
to jtschuster/runtime
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Sep 5, 2025
…nly (dotnet#119329) In the trimmer and ILC, we searched for backing fields with heuristics that validated a backing field had a `CompilerGeneratedAttribute`. In C# 14, the `field` keyword / semi-auto property feature means that some properties will have a compiler-generated field, but a user-written accessor. This can cause holes and unexpected behavior with the current heuristics. The semi-auto property accessors do not have `CompilerGeneratedAttribute`, so we can tighten the heuristic to only find backing fields when all accessors _and_ the found backing field have `CompilerGeneratedAttribute`. This should apply backing field propagation heuristics to properties with at least one auto accessor (e.g. `int Prop { get => field; set; }`) only (and also warns when it is unable to find the backing field for these). For all other properties, it is possible to annotate the backing field and accessors to achieve the same behavior. Additional context: dotnet#117072 (comment) and dotnet#117072 (comment)
jeffschwMSFT
pushed a commit
that referenced
this pull request
Sep 11, 2025
…nly (#119329) (#119407) In the trimmer and ILC, we searched for backing fields with heuristics that validated a backing field had a `CompilerGeneratedAttribute`. In C# 14, the `field` keyword / semi-auto property feature means that some properties will have a compiler-generated field, but a user-written accessor. This can cause holes and unexpected behavior with the current heuristics. The semi-auto property accessors do not have `CompilerGeneratedAttribute`, so we can tighten the heuristic to only find backing fields when all accessors _and_ the found backing field have `CompilerGeneratedAttribute`. This should apply backing field propagation heuristics to properties with at least one auto accessor (e.g. `int Prop { get => field; set; }`) only (and also warns when it is unable to find the backing field for these). For all other properties, it is possible to annotate the backing field and accessors to achieve the same behavior. Additional context: #117072 (comment) and #117072 (comment)
This was referenced Sep 17, 2025
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In the trimmer and ILC, we searched for backing fields with heuristics that validated a backing field had a
CompilerGeneratedAttribute. In C# 14, thefieldkeyword / semi-auto property feature means that some properties will have a compiler-generated field, but a user-written accessor. This can cause holes and unexpected behavior with the current heuristics. The semi-auto property accessors do not haveCompilerGeneratedAttribute, so we can tighten the heuristic to only find backing fields when all accessors and the found backing field haveCompilerGeneratedAttribute. This should apply backing field propagation heuristics to properties with at least one auto accessor (e.g.int Prop { get => field; set; }) only (and also warns when it is unable to find the backing field for these). For all other properties, it is possible to annotate the backing field and accessors to achieve the same behavior.Additional context: #117072 (comment) and #117072 (comment)