All codefix providers should have `SharedAttribute`

[Youssef1313]

Description

[Shared] is missing here:

runtime/src/libraries/System.Text.RegularExpressions/gen/UpgradeToRegexGeneratorCodeFixer.cs

Line 27 in 39d82c9

[ExportCodeFixProvider(LanguageNames.CSharp)]

and here:

runtime/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs

Line 23 in 39d82c9

[ExportCodeFixProvider(LanguageNames.CSharp)]

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Issue Details

---

Description

[Shared] is missing here:

runtime/src/libraries/System.Text.RegularExpressions/gen/UpgradeToRegexGeneratorCodeFixer.cs

Line 27 in 39d82c9

[ExportCodeFixProvider(LanguageNames.CSharp)]

and here:

runtime/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs

Line 23 in 39d82c9

[ExportCodeFixProvider(LanguageNames.CSharp)]

Reproduction Steps

.

Expected behavior

.

Actual behavior

.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	Youssef1313
Assignees:	-
Labels:	area-System.Runtime.InteropServices
Milestone:	-

[stephentoub]

What is [Shared]? Are you referring to

runtime/src/libraries/System.Composition.AttributedModel/src/System/Composition/SharedAttribute.cs

Line 16 in 9a0b8f3

public class SharedAttribute : PartMetadataAttribute

? Why is that needed?

This issue has been marked needs-author-action and may be missing some important information.

[jkoritzinsky]

CodeFixProviders are MEF components. Since they don't hold state (as per guidelines from Roslyn around their design), we can share a single instance in VS for all use cases. That's why we can mark it with [Shared].

[stephentoub]

Is "All codefix providers should have SharedAttribute" documented somewhere?

[Youssef1313]

I don't think it's documented. But roslyn and roslyn-analyzers follow this for the reason @jkoritzinsky stated.

[jkoritzinsky]

There's an analyzer and code-fix for it in Roslyn.Diagnostics.Analyzers at https://github.com/dotnet/roslyn-analyzers/blob/main/src/Roslyn.Diagnostics.Analyzers/Core/PartsExportedWithMEFv2MustBeMarkedAsShared.cs that should be tripping on the CodeFixProviders in dotnet/runtime, but I'm not sure why it isn't firing

[stephentoub]

that should be tripping on the CodeFixProviders in dotnet/runtime, but I'm not sure why it isn't firing

To my knowledge the Roslyn.Diagnostics.Analyzers are consumed by Roslyn. I don't believe we pull in or enable anything from that package.

[jkoritzinsky]

That would explain why it isn't firing in this repo. I must have had it fire one time when I was working in the Roslyn repo, which lead me to point out the guidance for roslyn-analyzers.