Adding <summary> to a class field.

[MartyIX]

Hi Roslyn enthusiasts,

I have these two approaches to add <summary> XML documentation to a class field in my Roslyn analyzer & fixer.

private async Task<Document> FixSummaryAsync(Document document, FieldDeclarationSyntax localFieldDeclaration, string comment, CancellationToken cancellationToken)
{
    SemanticModel? semanticModel = await document.GetSemanticModelAsync(cancellationToken);  

    // #1
    SyntaxTriviaList newDoc1 = SyntaxFactory.ParseLeadingTrivia($"/// <summary>{comment}</summary>\n");

    // #2
    XmlNodeSyntax summary = SyntaxFactory.XmlElement(
        SyntaxFactory.XmlElementStartTag(SyntaxFactory.XmlName("summary")),
        SyntaxFactory.List<XmlNodeSyntax>(new[] {
            SyntaxFactory.XmlText(SyntaxFactory.TokenList(
                SyntaxFactory.XmlTextLiteral(
                    SyntaxFactory.TriviaList(),
                    text: comment,
                    value: comment,
                    SyntaxFactory.TriviaList())))
        }),
        SyntaxFactory.XmlElementEndTag(SyntaxFactory.XmlName("summary"))
    );

    SyntaxTriviaList newDoc2 = SyntaxFactory.TriviaList(
        SyntaxFactory.Trivia(SyntaxFactory.DocumentationComment(summary, SyntaxFactory.XmlText("\n")))
    );

    DocumentationCommentTriviaSyntax? documentation = localFieldDeclaration.GetDocumentationCommentTriviaSyntax();

    if (documentation is null)
    {
        SyntaxNode? replacement = localFieldDeclaration.WithLeadingTrivia(newDoc1);
        // Replace the old local declaration with the new local declaration.
        SyntaxNode? oldRoot = await document.GetSyntaxRootAsync(cancellationToken);
        SyntaxNode? newRoot = oldRoot!.ReplaceNode(localFieldDeclaration, replacement);

        return document.WithSyntaxRoot(newRoot);
    }

    return document;
}

For some reason approach no. 2 adds also preserves correct indentation whereas approach no. 1 removes indentation of the field declaration.

Does anybody know how to fix approach no. 1?
Thank you

[svick]

I think there are some important things missing from the code you showed: newDoc1 is not a SyntaxNode, so it can't be used in ReplaceNode and newDoc2 is not even in the code. Could you show a more complete example? Ideally, it should be a method that actually compiles.

[MartyIX]

You are right. I have improved modified the code. Is the issue more clear now? If not, I can come up with a repro project but it will take some time.

[MartyIX]

This helps me to resolve my issue:

Replace

SyntaxNode? newRoot = oldRoot!.ReplaceNode(localFieldDeclaration, replacement);

with

SyntaxNode? newRoot = oldRoot!.ReplaceNode(localFieldDeclaration, replacement.WithAdditionalAnnotations(Formatter.Annotation));