More attributes recognized by the compiler (misc page?)

[jnm2]

Type of issue

Missing information

Description

These seem to match the theme of the existing misc page. They are attributes which are permitted in source and which provide access to specific compiler features or behaviors. (As opposed to #42850, which is more specifically about access to IL flags.)

• DeprecatedAttribute - Windows.Foundation.Metadata's take on ObsoleteAttribute

• EnumeratorCancellationAttribute - part of the async enumerators language feature

• ExperimentalAttribute - Windows.Foundation.Metadata's take which predated the one in System.Diagnostics.CodeAnalysis

• CollectionBuilderAttribute - part of the collection expressions language feature

• IndexerNameAttribute - enables C# authors to control the metadata name of an indexer, which would otherwise be Item. This attribute is not emitted into the binary; instead, the indexer's metadata name is set, and DefaultMemberAttribute is emitted on the containing type. By emitting DefaultMemberAttribute, the named indexer is still recognized downstream as being the default indexer despite not necessarily having the name Item.

• InlineArrayAttribute - part of the inline arrays language feature. Enables indexing and implicit casts to spans.

• InterceptsLocationAttribute - part of the interceptors compiler feature

• SetsRequiredMembersAttribute - part of the required members language feature

• UnmanagedCallersOnlyAttribute - part of the function pointers language feature, required for delegate* unmanaged<void> someFuncPointer = &SomeMethod;

• IUnknownConstantAttribute, IDispatchConstantAttribute - together with [Optional] on a parameter with no default value specified, tells the compiler whether to pass new UnknownWrapper(null) or new DispatchWrapper(null) rather than passing null. (Ref: https://github.com/dotnet/roslyn/blob/v4.2.0/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs#L1182-L1192)

Page URL

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/attributes/general

Content source URL

https://github.com/dotnet/docs/blob/main/docs/csharp/language-reference/attributes/general.md

Document Version Independent Id

6a60a627-c59c-74de-ce5b-6f52e15e7668

Article author

@BillWagner

Metadata

• ID: d415a929-c112-ab86-cf2e-13bf2ef64e1a
• Service: dotnet-csharp
• Sub-service: lang-reference

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