Fix analyzer RCS1253 (#1687)

Author: josefpihrt

ChangeLog.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix analyzer [RCS1043](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1043) ([PR](https://github.com/dotnet/roslynator/pull/1684))
 - Fix analyzer [RCS1213](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1213) ([PR](https://github.com/dotnet/roslynator/pull/1686))
   - Add unity method `OnRectTransformDimensionsChange` 
+- Fix analyzer [RCS1253](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1253) ([PR](https://github.com/dotnet/roslynator/pull/1687))
 - Fix refactoring [Check expression for null](https://josefpihrt.github.io/docs/roslynator/refactorings/RR0024) ([PR](https://github.com/dotnet/roslynator/pull/1682))
 
 ## [4.14.0] - 2025-07-26

src/Analyzers/CSharp/Analysis/FormatDocumentationCommentSummaryAnalyzer.cs

@@ -92,6 +92,20 @@ private static void AnalyzeSingleLineDocumentationCommentTrivia(SyntaxNodeAnalys
                     if (endTag?.IsMissing == false
                         && startTag.GetSpanEndLine() < endTag.GetSpanStartLine())
                     {
+                        foreach (XmlNodeSyntax node in summaryElement.Content)
+                        {
+                            if (node is XmlElementSyntax xmlElement)
+                            {
+                                switch (xmlElement.GetTag())
+                                {
+                                    case XmlTag.Code:
+                                    case XmlTag.List:
+                                    case XmlTag.Para:
+                                        return;
+                                }
+                            }
+                        }
+
                         Match match = SingleLineSummaryRegex.Match(
                             summaryElement.ToString(),
                             startTag.Span.End - summaryElement.SpanStart,

src/Tests/Analyzers.Tests/RCS1253FormatDocumentationCommentSummaryTests.cs

@@ -77,13 +77,13 @@ public async Task Test_ToSingleLine()
     {
         await VerifyDiagnosticAndFixAsync(@"
 /// [|<summary>
-/// a<code>b</code>c
+/// a<c>b</c>c
 /// </summary>|]
 class C
 {
 }
 ", @"
-/// <summary>a<code>b</code>c</summary>
+/// <summary>a<c>b</c>c</summary>
 class C
 {
 }
@@ -179,6 +179,19 @@ await VerifyNoDiagnosticAsync(@"
 class C
 {
 }
+", options: Options.AddConfigOption(ConfigOptionKeys.DocCommentSummaryStyle, ConfigOptionValues.DocCommentSummaryStyle_SingleLine));
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.FormatDocumentationCommentSummary)]
+    public async Task TestNoDiagnostic_ParaElement_ToSingleLine()
+    {
+        await VerifyNoDiagnosticAsync(@"
+/// <summary>
+/// <para>x</para>
+/// </summary>
+class C
+{
+}
 ", options: Options.AddConfigOption(ConfigOptionKeys.DocCommentSummaryStyle, ConfigOptionValues.DocCommentSummaryStyle_SingleLine));
     }
 }