diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.CSharp12.cs b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.CSharp12.cs
index bce7cd774b1..e5d655f2a0f 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.CSharp12.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.CSharp12.cs
@@ -1,10 +1,150 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using Person = (string name, string surname);
 
-class MyClass
+class WithAliasAnyType
 {
-    void AliasType(Person person)
+    void ValidCases(Person person)
     {
-        var a = (Person)person; // FN
+        _ = (Person)person;           // Compliant: not a duplicated cast
+    }
+
+    void InvalidCases(object obj)
+    {
+        if (obj is Person)            // FN: Person is alias for a struct
+        {
+            _ = (Person)obj;
+        }
+
+        if (obj is (string, string))  // FN: (string, string) and Person are equivalent
+        {
+            _ = (Person)obj;
+        }
+
+        if (obj is Person)            // FN: Person and (string, string) are equivalent
+        {
+            _ = ((string, string))obj;
+        }
+
+        if (obj is Person)            // FN: Person and (string ..., string) are equivalent
+        {
+            _ = ((string differentName1, string))obj;
+        }
+
+        if (obj is Person)            // FN: Person and (string, string ...) are equivalent
+        {
+            _ = ((string, string differentName2))obj;
+        }
+
+        if (obj is (string differentName1, string))  // FN: (string ..., string) and Person are equivalent
+        {
+            _ = (Person)obj;
+        }
+
+        if (obj is (string, string differentName2))  // FN: (string, string ...) and Person are equivalent
+        {
+            _ = (Person)obj;
+        }
     }
 }
+
+// https://github.com/SonarSource/sonar-dotnet/issues/223
+class Repro_223
+{
+    void NumericTypes(object obj)
+    {
+        if (obj is int)             // FN
+        {
+            _ = (int)obj;
+        }
+
+        if (obj is double)          // FN
+        {
+            _ = (double)obj;
+        }
+
+        if (obj is ushort)          // FN
+        {
+            _ = (ushort)obj;
+        }
+    }
+
+    void NullableValueTypes(object obj)
+    {
+        if (obj is int?)             // FN
+        {
+            _ = (int?)obj;
+        }
+
+        if (obj is byte?)            // FN
+        {
+            _ = (byte?)obj;
+        }
+    }
+
+    void UsingLanguageKeywordAndFrameworkName(object obj)
+    {
+        if (obj is Nullable<int>)    // FN
+        {
+            _ = (int?)obj;
+        }
+
+        if (obj is int?)             // FN
+        {
+            _ = (Nullable<int>)obj;
+        }
+
+        if (obj is IntPtr)           // FN
+        {
+            _ = (nint)obj;
+        }
+
+        if (obj is nint)             // FN
+        {
+            _ = (IntPtr)obj;
+        }
+
+        if (obj is System.UIntPtr)   // FN
+        {
+            _ = (nuint)obj;
+        }
+    }
+
+    void Enums(object obj)
+    {
+        if (obj is AnEnum)    // Noncompliant
+        {
+            _ = (AnEnum)obj;  // Secondary
+        }
+
+        if (obj is AnEnum?)   // FN
+        {
+            _ = (AnEnum?)obj;
+        }
+    }
+
+    void UserDefinedStructs(object obj)
+    {
+        if (obj is AStruct)            // FN
+        {
+            _ = (AStruct)obj;
+        }
+
+        if (obj is ARecordStruct)      // FN
+        {
+            _ = (ARecordStruct)obj;
+        }
+
+        if (obj is AReadonlyRefStruct) // FN
+        {
+            _ = (AStruct)obj;
+        }
+    }
+
+    enum AnEnum { Value1, Value2 }
+    struct AStruct { }
+    record struct ARecordStruct { }
+    readonly ref struct AReadonlyRefStruct { }
+}
+
+
diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.cs b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.cs
index ed562e5e95c..acc2aea409e 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/CastShouldNotBeDuplicated.cs
@@ -1,87 +1,84 @@
 using System;
 using System.Collections.Generic;
 
-namespace Tests.Diagnostics
+class Fruit { }
+
+class Program
 {
-    class Fruit { }
+    private object someField;
 
-    class Program
+    public void Foo(Object x)
     {
-        private object someField;
-
-        public void Foo(Object x)
+        if (x is Fruit)  // Noncompliant
         {
-            if (x is Fruit)  // Noncompliant
-            {
-                var f1 = (Fruit)x;
-//                       ^^^^^^^^ Secondary
-                var f2 = (Fruit)x;
-//                       ^^^^^^^^ Secondary
-            }
+            var f1 = (Fruit)x;
+//                   ^^^^^^^^ Secondary
+            var f2 = (Fruit)x;
+//                   ^^^^^^^^ Secondary
+        }
 
-            var f = x as Fruit;
-            if (x != null) // Compliant
-            {
+        var f = x as Fruit;
+        if (x != null) // Compliant
+        {
 
-            }
         }
+    }
 
-        public void Bar(object x)
+    public void Bar(object x)
+    {
+        if (!(x is Fruit))
         {
-            if (!(x is Fruit))
-            {
-                var f1 = (Fruit)x; // Compliant - but will throw
-            }
-            else
-            {
-                var f2 = (Fruit)x; // Compliant - should be non compliant
-            }
-
+            var f1 = (Fruit)x; // Compliant - but will throw
         }
+        else
+        {
+            var f2 = (Fruit)x; // Compliant - should be non compliant
+        }
+
+    }
 
-        public void FooBar(object x)
+    public void FooBar(object x)
+    {
+        if (x is int)
         {
-            if (x is int)
-            {
-                var res = (int)x; // Compliant because we are casting to a ValueType
-            }
+            var res = (int)x; // Compliant because we are casting to a ValueType
         }
+    }
 
-        // See https://github.com/SonarSource/sonar-dotnet/issues/2314
-        public void TakeIdentifierIntoAccount(object x)
+    // See https://github.com/SonarSource/sonar-dotnet/issues/2314
+    public void TakeIdentifierIntoAccount(object x)
+    {
+        if (x is Fruit)
         {
-            if (x is Fruit)
-            {
-                var f = new Fruit();
-                var c = (Fruit)f;
-            }
+            var f = new Fruit();
+            var c = (Fruit)f;
+        }
 
-            if (someField is Fruit) // Noncompliant
-            {
-                var fruit = (Fruit)this.someField;
-//                          ^^^^^^^^^^^^^^^^^^^^^ Secondary
-            }
+        if (someField is Fruit) // Noncompliant
+        {
+            var fruit = (Fruit)this.someField;
+//                      ^^^^^^^^^^^^^^^^^^^^^ Secondary
         }
+    }
 
-        public void UnknownFoo(object x)
+    public void UnknownFoo(object x)
+    {
+        if (x is Car)  // Compliant because we ignore what the type is // Error [CS0246]
         {
-            if (x is Car)  // Compliant because we ignore what the type is // Error [CS0246]
-            {
-                var c = (Car)x; // Error [CS0246]
-            }
+            var c = (Car)x; // Error [CS0246]
         }
     }
+}
 
-    public class Bar<T> { }
+public class Bar<T> { }
 
-    public class Foo<T>
+public class Foo<T>
+{
+    public void Process(object message)
     {
-        public void Process(object message)
+        if (message is Bar<T>/*comment*/)     // Noncompliant
         {
-            if (message is Bar<T>/*comment*/)     // Noncompliant
-            {
-                var sub = (Bar<T>/**/) message;   // Secondary
-            }
+            var sub = (Bar<T>/**/) message;   // Secondary
         }
     }
 }