Additional tab white space on XML comment leading trivia if Attribute is added prior

[elachlan]

I am currently working on this PR for CsWin32: microsoft/CsWin32#621

We have this code that causes the xml comment to have an extra leading tab white space:

typeDeclaration = typeDeclaration
                    .WithLeadingTrivia()
                    .AddAttributeLists(AttributeList().AddAttributes(GeneratedCodeAttribute))
                    .WithLeadingTrivia(typeDeclaration.GetLeadingTrivia());

typeDeclaration is MemberDeclarationSyntax.

The generated code attribute is:

private static readonly AttributeSyntax GeneratedCodeAttribute = Attribute(IdentifierName("global::System.CodeDom.Compiler.GeneratedCode"))
        .WithArgumentList(FixTrivia(AttributeArgumentList().AddArguments(
            AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(ThisAssembly.AssemblyName))),
            AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(ThisAssembly.AssemblyInformationalVersion))))));

If we do not add the attribute, then the leading trivia xml comment is formatted correctly.

Am I missing something obvious?

[Youssef1313]

typeDeclaration = typeDeclaration
                    .WithLeadingTrivia()
                    .AddAttributeLists(AttributeList().AddAttributes(GeneratedCodeAttribute))
                    .WithLeadingTrivia(typeDeclaration.GetLeadingTrivia());

I'm not seeing this line being hit with typeDeclaration corresponding to PInvoke in test TestSimpleMethod. Can you confirm?

It looks like trivia is messed up at WhitespaceRewriter

[elachlan]

Thank you for pointing me in the right direction!

[elachlan]

@Youssef1313, You can hit via HasGeneratedCodeAttribute test. I am fairly sure the issue is in VisitList. Though I am unsure how to solve it. It seems like it thinks that the XML comments are related to the attribute and not the class?

[Youssef1313]

@elachlan Yeah the doc comment trivia indeed belongs to the attribute.

[elachlan]

Should it belong to the class and not the attribute? This issue really only applied to comment trivia on classes with attributes. In VisitList we can't really test for that because the parent is null.

[Youssef1313]

Should it belong to the class and not the attribute?

Unfortunately, no. That's how trivia works. They're specifically attached to a token (more specifically, the first token of the method declaration). When there is an attribute, the first token of the method declaration is the [ (OpenBracketToken).

[Youssef1313]

Hope elachlan/CsWin32#1 corrects the implementation :)