Revert "first shot"

This reverts commit f0107a8.

Author: jonathanalgar

src/CustomCode-Analyzer/Analyzer.cs

@@ -1373,14 +1373,6 @@ private static bool IsValidParameterType(ITypeSymbol typeSymbol, Compilation com
                 return false;
             }
 
-            // If the type is nullable, unwrap it and check the underlying type
-            if (typeSymbol is INamedTypeSymbol named &&
-                named.OriginalDefinition.SpecialType == SpecialType.System_Nullable_T &&
-                named.TypeArguments.Length == 1)
-            {
-                typeSymbol = named.TypeArguments[0];
-            }
-
             // Check for primitive or special types
             if (ValidParameterSpecialTypes.Contains(typeSymbol.SpecialType))
             {

tests/CustomCode-Analyzer.Tests/AnalyzerTests.cs

@@ -1136,30 +1136,6 @@ await CSharpAnalyzerVerifier<Analyzer>.VerifyAnalyzerAsync(
             );
         }
 
-        [TestMethod]
-        public async Task UnsupportedParameterTypeRule_InGlobalScope_PublicField_NullableStruct_NoWarning()
-        {
-            var test =
-                @"
-[OSStructure]
-public struct NestedStructure
-{
-    public int Value;
-}
-
-[OSStructure]
-public struct MyStructure
-{
-    public NestedStructure? NullableNested;    // Nullable struct OK
-}
-";
-            await CSharpAnalyzerVerifier<Analyzer>.VerifyAnalyzerAsync(
-                test,
-                TestContext,
-                skipSDKreference: false
-            );
-        }
-
         // --------------- ParameterByReferenceRule (OS-ELG-MODL-05016) ------------
         [TestMethod]
         public async Task ParameterByReferenceRule_InGlobalScope_ReportsWarning()