S6964: Add FP repro for #9275 (#9281)

analyzers/tests/SonarAnalyzer.Test/Rules/AspNet/AvoidUnderPostingTest.cs

@@ -56,6 +56,7 @@ public class AvoidUnderPostingTest
     [TestMethod]
     public void AvoidUnderPosting_CSharp12() =>
         builder.AddPaths("AvoidUnderPosting.CSharp12.cs")
+            .AddReferences(NuGetMetadataReference.SystemTextJson("7.0.4"))
             .WithOptions(ParseOptionsHelper.FromCSharp12)
             .Verify();
 

analyzers/tests/SonarAnalyzer.Test/TestCases/AspNet/AvoidUnderPosting.CSharp12.cs

@@ -1,5 +1,7 @@
 using Microsoft.AspNetCore.Mvc;
+using System;
 using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
 
 namespace CSharp12
 {
@@ -20,3 +22,25 @@ public class DerivedFromController : Controller
         [HttpDelete] public IActionResult Remove(ModelWithPrimaryAndParameterlessConstructor model) => View(model);
     }
 }
+
+namespace Repro9275
+{
+    // Repro https://github.com/SonarSource/sonar-dotnet/issues/9275
+    public class Model
+    {
+        public int ValueProperty { get; set; }        // Noncompliant
+
+        [Custom]                                      // Noncompliant repro for https://github.com/SonarSource/sonar-dotnet/issues/9282
+        public int ValuePropertyAnnotatedWithCustomAttribute { get; set; }
+
+        [JsonRequired]                                // Noncompliant - FP because the attribute is annotated with JsonRequiredAttribute
+        public int AnotherValueProperty { get; set; }
+    }
+
+    public class DerivedFromController : Controller
+    {
+        [HttpPost] public IActionResult Create(Model model) => View(model);
+    }
+
+    public class CustomAttribute : Attribute { }
+}