From a720d7fdb33518001cef3a78b07076a0d3f8a330 Mon Sep 17 00:00:00 2001
From: Pavel Mikula
 <57188685+pavel-mikula-sonarsource@users.noreply.github.com>
Date: Tue, 6 Jun 2023 15:46:59 +0200
Subject: [PATCH] S3063: Add FP repro for #7324 (#7331)

---
 .../TestCases/UnusedStringBuilder.cs          | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/UnusedStringBuilder.cs b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/UnusedStringBuilder.cs
index 14c4cd04369..b763dcec213 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/UnusedStringBuilder.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/UnusedStringBuilder.cs
@@ -121,3 +121,40 @@ public static class StringBuilderExtensions
 {
     public static string ToStringAndFree(this StringBuilder sb) => string.Empty;
 }
+
+// https://github.com/SonarSource/sonar-dotnet/issues/7324
+public class Repro_7324
+{
+    public string Concat_Prefix()
+    {
+        var sb = new StringBuilder();   // Noncompliant FP
+        sb.Append("Lorem ipsum");
+        var ret = "Prefix: " + sb;
+        return ret;
+    }
+
+    public string Concat_Infix()
+    {
+        var sb = new StringBuilder();   // Noncompliant FP
+        sb.Append("Lorem ipsum");
+        var ret = "Prefix: " + sb + " suffix";
+        return ret;
+    }
+
+    public string Concat_Suffix()
+    {
+        var sb = new StringBuilder();   // Noncompliant FP
+        sb.Append("Lorem ipsum");
+        var ret = sb + " suffix";
+        return ret;
+    }
+
+    public string Concat_OutsideDeclaration()
+    {
+        var sb = new StringBuilder();   // Noncompliant FP
+        sb.Append("Lorem ipsum");
+        string ret;
+        ret = "Prefix: " + sb;
+        return ret;
+    }
+}