Mark descriptor-preserved members as reflection-visible by sbomer · Pull Request #128272 · dotnet/runtime

sbomer · 2026-05-15T22:55:21Z

And mark their declaring types as reflection-visible.

When a member is marked via descriptor it should be considered visible to reflection. And when that is the case, its declaring type is accessible via reflection, so the requirements for reflection-visible types should be preserved too.

Fixes #128120

…t impls Add a regression test for dotnet#128120. When a type is preserved via an XML descriptor, ILLink should keep its static abstract interface implementations if those methods are called through constrained generics elsewhere in the program. Currently the test fails because ILLink strips the interface and override from the descriptor-preserved type. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

…ant casting A method preserved via XML descriptor is reflection-visible, which means its declaring type is also accessible (e.g., via MethodBase.GetCurrentMethod().DeclaringType) and could be used as a generic argument in constrained calls (e.g., via MakeGenericMethod). Mark the declaring type as relevant to variant casting so that its static abstract interface implementations are preserved by the linker. Fixes dotnet#128120 Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

…t be kept Test that a reference type with explicit layout preserved via XML descriptor retains its fields. This verifies the type is treated as fully reflection-visible (MarkImplicitlyUsedFields), not just relevant to variant casting. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

…tion-visible Descriptor-preserved methods and fields are reflection-visible. Their declaring types are also accessible (e.g., via MethodBase.DeclaringType or FieldInfo.DeclaringType) and could be used as generic arguments in constrained calls via MakeGenericMethod. Defer full reflection-visible treatment from DescriptorMarker to MarkStep via pending sets in Annotations, so that MarkStep can call MarkMethodVisibleToReflection, MarkFieldVisibleToReflection, and MarkTypeVisibleToReflection on the declaring type. This ensures: - Static abstract interface implementations are preserved - Implicit fields for explicit-layout types are preserved - Metadata names are not swept - TypeMap entries are processed Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

Clarify that GetCurrentMethod produces IL2026 but the suppression is justified because the descriptor preserves the method. Add ExpectedNoWarnings to the explicit layout test. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

- Remove unnecessary #pragma warning disable IL2060 from tests - Add ExpectedNoWarnings to explicit layout test - Remove issue references from test comments - Clarify comment about IL2026 suppression justification - Expose pending sets as properties, inline clear in ProcessMarkedPending - Separate doc comments for method and field pending sets Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

…entations (dotnet#128020)" This reverts commit c196cc0.

Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

dotnet-policy-service · 2026-05-15T22:56:45Z

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Copilot

Pull request overview

This PR updates the ILLink marking pipeline so that members preserved via XML descriptors are treated as reflection-visible, and it additionally marks their declaring types as reflection-visible to preserve reflection-dependent semantics (e.g., variant casting behaviors and explicit-layout field preservation).

Changes:

Add pending-tracking for descriptor-preserved methods/fields and process them in MarkStep via Mark*VisibleToReflection, also marking declaring types reflection-visible.
Extend DescriptorMarker to schedule descriptor-preserved fields/methods for reflection-visible processing.
Add new linker test cases + descriptors validating static abstract interface implementations and explicit-layout fields are preserved when reachability is via descriptor-preserved members.

Show a summary per file

File	Description
src/tools/illink/src/linker/Linker/Annotations.cs	Adds pending collections/APIs to schedule descriptor-preserved members for reflection-visible processing.
src/tools/illink/src/linker/Linker.Steps/MarkStep.cs	Drains pending reflection-visible members and marks members + declaring types as reflection-visible.
src/tools/illink/src/linker/Linker.Steps/DescriptorMarker.cs	Schedules descriptor-preserved fields/methods for reflection-visible handling.
src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/StaticAbstractMethodsPreservedViaDescriptor.cs	New regression test for static abstract interface implementations preserved via descriptor reachability.
src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/StaticAbstractMethodsPreservedViaDescriptor.xml	Descriptor roots methods used by the static-abstract preservation test.
src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/DescriptorPreservedTypeIsReflectionVisible.cs	New test validating descriptor-preserved type is fully treated as reflection-visible (variant casting + explicit layout fields).
src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/DescriptorPreservedTypeIsReflectionVisible.xml	Descriptor roots methods used by the reflection-visible type behavior test.

Copilot's findings

Files reviewed: 8/8 changed files
Comments generated: 3

ILTrim does not support static abstract interface methods or descriptor-based reflection-visible marking. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

- Convert tabs to spaces in test files to match .editorconfig - Remove spaces before parentheses to match neighbor test style - Make pending reflection-visible APIs internal Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

Pass DependencyInfo and MessageOrigin from DescriptorMarker through to MarkStep so warnings and dependency tracking attribute correctly to the descriptor XML location. Encapsulate the pending data behind a DrainPendingReflectionVisibleMembers method. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

Copilot

Copilot's findings

Files reviewed: 9/9 changed files
Comments generated: 2

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

Copilot

Copilot's findings

Files reviewed: 9/9 changed files
Comments generated: 1

+        internal List<(MethodDefinition Method, DependencyInfo Reason, MessageOrigin Origin)> DrainPendingReflectionVisibleMethods()
+        {
+            var result = pending_reflection_visible_methods;
+            pending_reflection_visible_methods = new List<(MethodDefinition, DependencyInfo, MessageOrigin)>();
+            return result;
+        }
+
+        internal List<(FieldDefinition Field, DependencyInfo Reason, MessageOrigin Origin)> DrainPendingReflectionVisibleFields()
+        {
+            var result = pending_reflection_visible_fields;
+            pending_reflection_visible_fields = new List<(FieldDefinition, DependencyInfo, MessageOrigin)>();


sbomer and others added 8 commits May 15, 2026 15:51

Revert "Work around illink incorrectly trimming static virtual implem…

1675d7b

…entations (dotnet#128020)" This reverts commit c196cc0.

Remove verbose comments from descriptor and MarkStep changes

323fb3e

Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

Copilot AI review requested due to automatic review settings May 15, 2026 22:55

Copilot started reviewing on behalf of sbomer May 15, 2026 22:55 View session

github-actions Bot added the area-Tools-ILLink .NET linker development as well as trimming analyzers label May 15, 2026

dotnet-policy-service Bot added the linkable-framework Issues associated with delivering a linker friendly framework label May 15, 2026

dotnet-policy-service Bot assigned sbomer May 15, 2026

github-project-automation Bot added this to AppModel May 15, 2026

sbomer force-pushed the descriptor-abstract branch from bf799c8 to 323fb3e Compare May 15, 2026 22:56

Copilot AI reviewed May 15, 2026

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Comment thread src/tools/illink/src/linker/Linker.Steps/MarkStep.cs Outdated

Comment thread src/tools/illink/src/linker/Linker/Annotations.cs Outdated

Comment thread ...Inheritance.Interfaces/StaticInterfaceMethods/StaticAbstractMethodsPreservedViaDescriptor.cs Outdated

sbomer and others added 3 commits May 15, 2026 16:35

Add new descriptor tests to ILTrim expected failures baseline

d98a9b3

ILTrim does not support static abstract interface methods or descriptor-based reflection-visible marking. Co-authored-by: Copilot <[email protected]> Assisted-by: Claude:claude-opus-4.6-1m

sbomer requested a review from Copilot May 15, 2026 23:50

Copilot started reviewing on behalf of sbomer May 15, 2026 23:51 View session

Copilot AI reviewed May 15, 2026

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Comment thread src/tools/illink/src/linker/Linker/Annotations.cs Outdated

Comment thread src/coreclr/System.Private.CoreLib/src/ILLink/ILLink.Descriptors.Shared.xml

Potential fix for pull request finding

5969d66

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

Copilot AI review requested due to automatic review settings May 16, 2026 00:03

Copilot started reviewing on behalf of sbomer May 16, 2026 00:03 View session

Copilot AI reviewed May 16, 2026

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Mark descriptor-preserved members as reflection-visible#128272

Mark descriptor-preserved members as reflection-visible#128272
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