Fix single line summary when changing the reference

The issue resulted from always passing in a newline character
when using the code fix provider. This was resolved by determining
if the summary was multiline or not. If it isn't multiline the newLineText
is no longer passed.

Author: tokarzkj

StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/DocumentationRules/SA1642SA1643CodeFixProvider.cs

@@ -117,6 +117,24 @@ internal static ImmutableArray<string> GenerateStandardText(Document document, B
             }
         }
 
+        internal static SyntaxList<XmlNodeSyntax> BuildStandardTextSyntaxList(BaseTypeDeclarationSyntax typeDeclaration, string preText, string postText)
+        {
+            TypeParameterListSyntax typeParameterList;
+            if (typeDeclaration is ClassDeclarationSyntax classDeclaration)
+            {
+                typeParameterList = classDeclaration.TypeParameterList;
+            }
+            else
+            {
+                typeParameterList = (typeDeclaration as StructDeclarationSyntax)?.TypeParameterList;
+            }
+
+            return XmlSyntaxFactory.List(
+                XmlSyntaxFactory.Text(preText),
+                BuildSeeElement(typeDeclaration.Identifier, typeParameterList),
+                XmlSyntaxFactory.Text(postText.EndsWith(".") ? postText : (postText + ".")));
+        }
+
         internal static SyntaxList<XmlNodeSyntax> BuildStandardTextSyntaxList(BaseTypeDeclarationSyntax typeDeclaration, string newLineText, string preText, string postText)
         {
             TypeParameterListSyntax typeParameterList;
@@ -143,8 +161,6 @@ private static Task<Document> GetTransformedDocumentAsync(Document document, Syn
 
             var standardText = GenerateStandardText(document, declarationSyntax, typeDeclaration, cancellationToken);
 
-            string newLineText = document.Project.Solution.Workspace.Options.GetOption(FormattingOptions.NewLine, LanguageNames.CSharp);
-
             string trailingString = string.Empty;
 
             var newContent = RemoveMalformattedStandardText(node.Content, standardText[0], standardText[1], ref trailingString);
@@ -157,7 +173,18 @@ private static Task<Document> GetTransformedDocumentAsync(Document document, Syn
                 }
             }
 
-            var list = BuildStandardTextSyntaxList(typeDeclaration, newLineText, standardText[0], standardText[1] + trailingString);
+            SyntaxList<XmlNodeSyntax> list;
+            if (IsMultiLine(node))
+            {
+                string newLineText = document.Project.Solution.Workspace.Options.GetOption(FormattingOptions.NewLine, LanguageNames.CSharp);
+                list = BuildStandardTextSyntaxList(typeDeclaration, newLineText, standardText[0], standardText[1] + trailingString);
+            }
+            else
+            {
+                list = BuildStandardTextSyntaxList(typeDeclaration, standardText[0], standardText[1] + trailingString);
+            }
+
+            
             newContent = newContent.InsertRange(0, list);
 
             newContent = RemoveTrailingEmptyLines(newContent);
@@ -171,6 +198,12 @@ private static Task<Document> GetTransformedDocumentAsync(Document document, Syn
             return Task.FromResult(newDocument);
         }
 
+        private static bool IsMultiLine(XmlElementSyntax node)
+        {
+            var lineSpan = node.GetLineSpan();
+            return lineSpan.StartLinePosition.Line != lineSpan.EndLinePosition.Line;
+        }
+
         private static Task<Document> GetTransformedDocumentAsync(Document document, SyntaxNode root, XmlEmptyElementSyntax node)
         {
             var typeDeclaration = node.FirstAncestorOrSelf<BaseTypeDeclarationSyntax>();

StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1642UnitTests.cs

@@ -939,8 +939,7 @@ public ClassName()
 {{
     public class ClassName
     {{
-        /// <summary>
-        /// Initializes a new instance of the <see cref=""ClassName""/> class.</summary>
+        /// <summary>Initializes a new instance of the <see cref=""ClassName""/> class.</summary>
         public ClassName()
         {{
         }}
@@ -951,6 +950,30 @@ public ClassName()
             await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
         }
 
+        [Fact]
+        [WorkItem(2963, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/2963")]
+        public async Task TestConstructorNoCRefDocumentationSingleLineAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    /// <summary>Initializes a new instance of the TestClass class.</summary>
+    public TestClass() { }
+}
+";
+
+            var fixedCode = @"
+public class TestClass
+{
+    /// <summary>Initializes a new instance of the <see cref=""TestClass""/> class.</summary>
+    public TestClass() { }
+}
+";
+
+            var expected = Diagnostic().WithLocation(4, 9);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
         [Theory]
         [WorkItem(2686, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/2686")]
         [InlineData("")]