Add ExtensionMarkerAttribute #118188
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Add ExtensionMarkerAttribute #118188
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Pull Request Overview
This PR adds a new ExtensionMarkerAttribute class to support a language feature for associating extension members with specific marker types. The attribute is designed for compiler use and includes appropriate metadata to discourage direct developer usage.
Key Changes
- Adds new
ExtensionMarkerAttributeclass with aNameproperty for marker type association - Includes comprehensive attribute metadata (
EditorBrowsable,AttributeUsage) to control visibility and usage - Provides complete implementation with API surface, tests, and project configuration
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/ExtensionMarkerAttribute.cs |
New attribute implementation with constructor, Name property, and XML documentation |
src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems |
Adds the new file to the build configuration |
src/libraries/System.Runtime/ref/System.Runtime.cs |
Adds the public API surface definition for the new attribute |
src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/CompilerServices/AttributesTests.cs |
Adds unit tests to verify constructor and Name property functionality |
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CC. @jeffhandley for M1 approval. This is just the attribute used by Roslyn for the extension member feature so it can avoid synthesizing it into every assembly. |
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Closes #118179
Relates to feature test plan dotnet/roslyn#76130