[Interop] AddGeneratedComClassFixer: remove [ComVisible(true)] during conversion

[Copilot]

The AddGeneratedComClassFixer code fix was not removing [ComVisible(true)] when converting a class to use [GeneratedComClass], leaving a redundant legacy attribute alongside the new one. This includes cases where [ComVisible(true)] appears on a different partial declaration in a separate file.

Description

• ConvertToSourceGeneratedInteropFixer.cs: Changed the fix delegate type from Func<DocumentEditor, CancellationToken, Task> to Func<SolutionEditor, DocumentId, CancellationToken, Task> throughout (base class, RegisterCodeFixesAsync, ApplyActionAndEnableUnsafe, and CustomFixAllProvider). This enables fixers to edit multiple documents in a single code action, which is necessary for cross-document attribute removal.
• AddGeneratedComClassFixer.cs: Rewrote AddGeneratedComClassAsync to use SolutionEditor. Now obtains the INamedTypeSymbol before applying edits, removes all [ComVisible(true)] attributes (not just the first) across any partial declarations, and uses solutionEditor.OriginalSolution.GetDocumentId(syntaxRef.SyntaxTree) to find which document each attribute lives in — safely handling cross-document, same-document, and metadata (null) cases.
• ConvertComImportToGeneratedComInterfaceFixer.cs and ConvertToLibraryImportFixer.cs: Updated CreateFixForSelectedOptions to use the new solution-level signature; each implementation obtains its DocumentEditor from the SolutionEditor internally.
• AddGeneratedComClassTests.cs: Added four tests:
  • TypeWithComVisibleTrue_RemovesComVisibleAttribute — [ComVisible(true)] is removed (same declaration)
  • TypeWithComVisibleFalse_PreservesComVisibleAttribute — [ComVisible(false)] is preserved (different semantics)
  • TypeWithComVisibleTrueOnSecondPartialDeclaration_RemovesComVisibleAttribute — [ComVisible(true)] on a second partial declaration in the same file is removed
  • TypeWithComVisibleTrueInSeparateFile_RemovesComVisibleAttribute — [ComVisible(true)] on a partial declaration in a separate file is removed correctly

Before fix, applying the codefix to:

[ComVisible(true)]
class C : I { }

would produce [ComVisible(true)][GeneratedComClass] partial class C : I. After, it correctly produces [GeneratedComClass] partial class C : I — even when [ComVisible(true)] is on a different partial declaration in another file.

Customer Impact

Users applying the "convert to GeneratedComClass" codefix are left with a stale [ComVisible(true)] attribute that has no effect in the new model and causes unnecessary noise/confusion. This applies whether the attribute is on the same declaration or any other partial declaration of the class, including those in separate files.

Regression

No — this is a missing feature in the codefix, not a regression.

Testing

8 unit tests in ComInterfaceGenerator.Unit.Tests (including the 4 new ones), all passing. Full suite of 852 tests passes. LibraryImportGenerator unit tests (95 tests) also pass, confirming no regressions in the refactored base class.

Risk

Low. Change is isolated to the Roslyn analyzer/fixer; only affects the code transformation applied by the IDE codefix. Runtime behavior is unchanged. The base class refactoring to SolutionEditor is a pure internal restructuring — all existing fixer behavior is preserved.

Original prompt

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This section details on the original issue you should resolve

<issue_title>GeneratedComClass codefix doesn't remove [ComVisible(true)] from classes</issue_title>
<issue_description>If [ComVisible(true)] is present on a class converted to a GeneratedComClass, the codefixer should remove the attribute.</issue_description>

Comments on the Issue (you are @copilot in this section)

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Issue Details

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If [ComVisible(true)] is present on a class converted to a GeneratedComClass, the codefixer should remove the attribute.

Author:	jtschuster
Assignees:	-
Labels:	area-System.Runtime.InteropServices, code-analyzer
Milestone:	9.0.0

• Fixes GeneratedComClass codefix doesn't remove [ComVisible(true)] from classes #94429

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[jkoritzinsky]

@copilot please add another test where the class we will apply the fixer to has two partial definitions and the [ComVisible(true)] attribute is on the second one.

[Copilot]

@copilot please add another test where the class we will apply the fixer to has two partial definitions and the [ComVisible(true)] attribute is on the second one.

Added in b2e5714. The test TypeWithComVisibleTrueOnSecondPartialDeclaration_RemovesComVisibleAttribute has the first partial declaration (without [ComVisible(true)]) triggering the diagnostic, while the second partial declaration carries [ComVisible(true)]. The fixer correctly removes it from the second partial since GetDeclaredSymbol returns the full INamedTypeSymbol with attributes from all partial declarations.

[Copilot]

Pull request overview

Updates the ComInterfaceGenerator Roslyn code fix so converting a class to [GeneratedComClass] also removes redundant legacy [ComVisible(true)] attributes, reducing noise and aligning the produced code with the source-generated COM model.

Changes:

• Updated AddGeneratedComClassFixer to find and remove [ComVisible(true)] during the conversion.
• Made the fixer path async and added semantic checks using SymbolEqualityComparer.Default.
• Added unit tests validating removal/preservation behavior (including a same-file second partial declaration case).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/libraries/System.Runtime.InteropServices/gen/ComInterfaceGenerator/Analyzers/AddGeneratedComClassFixer.cs	Removes [ComVisible(true)] while applying [GeneratedComClass] and partial.
src/libraries/System.Runtime.InteropServices/tests/ComInterfaceGenerator.Unit.Tests/AddGeneratedComClassTests.cs	Adds tests for [ComVisible(true)] removal, [ComVisible(false)] preservation, and partial declarations.

[Copilot]

comVisibleAttr.ApplicationSyntaxReference can point to an attribute on a different partial declaration in another document. In that case syntaxRef.GetSyntaxAsync(ct) returns a node from a different SyntaxTree, and DocumentEditor.RemoveNode will fail because the node is not part of the current document being edited. Please guard against cross-document syntax references (e.g., only remove when syntaxRef.SyntaxTree matches the current document) or rework the code action to edit the containing document/solution as needed.

Suggested change

	editor.RemoveNode(comVisibleAttrSyntax);
	if (comVisibleAttrSyntax.SyntaxTree == editor.OriginalRoot.SyntaxTree)
	{
	editor.RemoveNode(comVisibleAttrSyntax);
	}

[jkoritzinsky]

@copilot please address the feedback from @copilot by adjusting the code fixer here to be a SolutionEditor and editing across documents when needed.

[Copilot]

@copilot please address the feedback from @copilot by adjusting the code fixer here to be a SolutionEditor and editing across documents when needed.

Done in eeafcc6. The fix now:

1. Changed ConvertToSourceGeneratedInteropFixer to use Func<SolutionEditor, DocumentId, CancellationToken, Task> throughout (base class, fix-all provider, and RegisterCodeFixesAsync) so all fixers now operate at the solution level.
2. AddGeneratedComClassFixer uses solutionEditor.OriginalSolution.GetDocumentId(syntaxRef.SyntaxTree) to find which document each [ComVisible(true)] attribute lives in, then calls solutionEditor.GetDocumentEditorAsync(attrDocumentId, ct) to get the right editor — handling cross-document and same-document cases uniformly.
3. All [ComVisible(true)] attributes are now removed (not just the first) via .Where(...).ToArray() + a foreach loop.
4. Added a cross-document test TypeWithComVisibleTrueInSeparateFile_RemovesComVisibleAttribute where the attribute is in a separate source file.
5. ConvertComImportToGeneratedComInterfaceFixer and ConvertToLibraryImportFixer updated to use the new signature.