private async Task <Document> GetTransformedDocumentAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken) { var documentRoot = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false); SyntaxNode syntax = documentRoot.FindNode(diagnostic.Location.SourceSpan); if (syntax == null) { return(document); } PropertyDeclarationSyntax propertyDeclarationSyntax = syntax.FirstAncestorOrSelf <PropertyDeclarationSyntax>(); if (propertyDeclarationSyntax == null) { return(document); } DocumentationCommentTriviaSyntax documentationComment = propertyDeclarationSyntax.GetDocumentationCommentTriviaSyntax(); if (documentationComment == null) { return(document); } if (!(documentationComment.Content.GetFirstXmlElement(XmlCommentHelper.SummaryXmlTag) is XmlElementSyntax summaryElement)) { return(document); } SyntaxList <XmlNodeSyntax> summaryContent = summaryElement.Content; if (!this.TryRemoveSummaryPrefix(ref summaryContent, "Gets or sets ")) { if (!this.TryRemoveSummaryPrefix(ref summaryContent, "Gets ")) { this.TryRemoveSummaryPrefix(ref summaryContent, "Sets "); } } SyntaxList <XmlNodeSyntax> content = summaryContent.WithoutFirstAndLastNewlines(); if (!string.IsNullOrWhiteSpace(content.ToFullString())) { // wrap the content in a <placeholder> element for review content = XmlSyntaxFactory.List(XmlSyntaxFactory.PlaceholderElement(content)); } string newLineText = document.Project.Solution.Workspace.Options.GetOption(FormattingOptions.NewLine, LanguageNames.CSharp); XmlElementSyntax valueElement = XmlSyntaxFactory.MultiLineElement(XmlCommentHelper.ValueXmlTag, newLineText, content); XmlNodeSyntax leadingNewLine = XmlSyntaxFactory.NewLine(newLineText); // HACK: The formatter isn't working when contents are added to an existing documentation comment, so we // manually apply the indentation from the last line of the existing comment to each new line of the // generated content. SyntaxTrivia exteriorTrivia = GetLastDocumentationCommentExteriorTrivia(documentationComment); if (!exteriorTrivia.Token.IsMissing) { leadingNewLine = leadingNewLine.ReplaceExteriorTrivia(exteriorTrivia); valueElement = valueElement.ReplaceExteriorTrivia(exteriorTrivia); } // Try to replace an existing <value> element if the comment contains one. Otherwise, add it as a new element. SyntaxNode root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false); SyntaxNode newRoot; XmlNodeSyntax existingValue = documentationComment.Content.GetFirstXmlElement(XmlCommentHelper.ValueXmlTag); if (existingValue != null) { newRoot = root.ReplaceNode(existingValue, valueElement); } else { DocumentationCommentTriviaSyntax newDocumentationComment = documentationComment.WithContent( documentationComment.Content.InsertRange( documentationComment.Content.Count - 1, XmlSyntaxFactory.List(leadingNewLine, valueElement))); newRoot = root.ReplaceNode(documentationComment, newDocumentationComment); } return(document.WithSyntaxRoot(newRoot)); }