Fix RCS1197

ChangeLog.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix [RCS1084](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1084.md) ([#1085](https://github.com/josefpihrt/roslynator/pull/1085)).
 - Fix [RCS1169](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1169.md) ([#1092](https://github.com/JosefPihrt/Roslynator/pull/1092)).
 - Recognize more shapes of IAsyncEnumerable as being Async ([RCS1047](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1047.md)) ([#1084](https://github.com/josefpihrt/roslynator/pull/1084)).
+- Fix [RCS1197](https://github.com/JosefPihrt/Roslynator/blob/main/docs/analyzers/RCS1197.md) ([#1093](https://github.com/JosefPihrt/Roslynator/pull/1093)).
 
 ## [4.3.0] - 2023-04-24
 

src/Tests/Analyzers.Tests/RCS1197OptimizeStringBuilderAppendCallTests.cs

@@ -526,6 +526,38 @@ void M()
 ");
     }
 
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.OptimizeStringBuilderAppendCall)]
+    public async Task Test_InterpolatedString_WithFormat_AppendLine2()
+    {
+        await VerifyDiagnosticAndFixAsync(@"
+using System;
+using System.Text;
+
+class C
+{
+    void M(DateTime x)
+    {
+        string s = null;
+        var sb = new StringBuilder();
+        sb.Append([|$@""{x:hh\:mm\:ss\.fff}""|]).ToString();
+    }
+}
+", @"
+using System;
+using System.Text;
+
+class C
+{
+    void M(DateTime x)
+    {
+        string s = null;
+        var sb = new StringBuilder();
+        sb.AppendFormat(@""{0:hh\:mm\:ss\.fff}"", x).ToString();
+    }
+}
+");
+    }
+
     [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.OptimizeStringBuilderAppendCall)]
     public async Task Test_Concatenation()
     {

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

@@ -35,6 +35,9 @@ public static (SyntaxKind contentKind, string methodName, ImmutableArray<Argumen
                     {
                         StringBuilder sb = StringBuilderCache.GetInstance();
 
+                        if (isVerbatim)
+                            sb.Append("@");
+
                         sb.Append("\"{0");
 
                         if (alignmentClause is not null)