Fix analyzer RCS1223 - handle type declaration with no braces (#1552)

Author: josefpihrt

ChangeLog.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fix analyzer [RCS0053](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS0053) ([PR](https://github.com/dotnet/roslynator/pull/1547))
+- Fix analyzer [RCS1223](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1223) ([PR](https://github.com/dotnet/roslynator/pull/1552))
 
 ## [4.12.7] - 2024-10-01
 

src/Tests/Analyzers.Tests/RCS1223MarkTypeWithDebuggerDisplayAttributeTests.cs

@@ -312,6 +312,31 @@ private string DebuggerDisplay
         }
     }
 }
+""");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.MarkTypeWithDebuggerDisplayAttribute)]
+    public async Task Test_PublicReadOnlyRefStruct()
+    {
+        await VerifyDiagnosticAndFixAsync("""
+using System.Diagnostics;
+
+public readonly ref struct [|Dummy|];
+""", """
+using System.Diagnostics;
+
+[DebuggerDisplay("{DebuggerDisplay,nq}")]
+public readonly ref struct Dummy
+{
+    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+    private string DebuggerDisplay
+    {
+        get
+        {
+            return "";
+        }
+    }
+}
 """);
     }
 }

src/Workspaces.Common/CSharp/Refactorings/MarkTypeWithDebuggerDisplayAttributeRefactoring.cs

@@ -3,6 +3,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
 using static Roslynator.CSharp.CSharpFactory;
@@ -16,7 +17,16 @@ public static async Task<Document> RefactorAsync(
         TypeDeclarationSyntax typeDeclaration,
         CancellationToken cancellationToken)
     {
-        int position = typeDeclaration.OpenBraceToken.Span.End;
+        TypeDeclarationSyntax newTypeDeclaration = typeDeclaration;
+
+        if (typeDeclaration.OpenBraceToken.IsKind(SyntaxKind.None))
+        {
+            newTypeDeclaration = typeDeclaration.WithSemicolonToken(default)
+                .WithOpenBraceToken(OpenBraceToken())
+                .WithCloseBraceToken(CloseBraceToken());
+        }
+
+        int position = newTypeDeclaration.Identifier.Span.End;
 
         SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
 
@@ -27,9 +37,15 @@ public static async Task<Document> RefactorAsync(
                 ParseName("System.Diagnostics.DebuggerDisplayAttribute").WithSimplifierAnnotation(),
                 AttributeArgument(LiteralExpression($"{{{propertyName},nq}}"))));
 
-        PropertyDeclarationSyntax propertyDeclaration = DebuggerDisplayPropertyDeclaration(propertyName, InvocationExpression(IdentifierName("ToString")));
+        INamedTypeSymbol typeSymbol = semanticModel.GetDeclaredSymbol(typeDeclaration, cancellationToken)!;
+
+        ExpressionSyntax returnExpression = (typeSymbol.TypeKind == TypeKind.Struct && typeSymbol.IsRefLikeType)
+            ? StringLiteralExpression("")
+            : InvocationExpression(IdentifierName("ToString"));
+
+        PropertyDeclarationSyntax propertyDeclaration = DebuggerDisplayPropertyDeclaration(propertyName, returnExpression);
 
-        TypeDeclarationSyntax newTypeDeclaration = SyntaxRefactorings.AddAttributeLists(typeDeclaration, keepDocumentationCommentOnTop: true, attributeList);
+        newTypeDeclaration = SyntaxRefactorings.AddAttributeLists(newTypeDeclaration, keepDocumentationCommentOnTop: true, attributeList);
 
         newTypeDeclaration = MemberDeclarationInserter.Default.Insert(newTypeDeclaration, propertyDeclaration);