Update

Author: muukii

Sources/StateStructMacros/KnownTypes.swift

@@ -105,6 +105,19 @@ enum KnownTypes {
   ]
 
   static func isPrimitiveType(_ typeName: String) -> Bool {
-    primitiveTypes.contains(typeName)
+    
+    if typeName.hasSuffix("?") {
+      let unwrappedTypeName = typeName.replacingOccurrences(of: "?", with: "")      
+      return isPrimitiveType(unwrappedTypeName)
+    }
+    
+    if typeName.hasPrefix("Optional<") && typeName.hasSuffix(">") {
+      let unwrappedTypeName = typeName
+        .replacingOccurrences(of: "Optional<", with: "")
+        .replacingOccurrences(of: ">", with: "")
+      return isPrimitiveType(unwrappedTypeName)
+    }
+    
+    return primitiveTypes.contains(typeName)
   }
 } 

Tests/StateStructMacroTests/TrackingMacroTests.swift

@@ -15,6 +15,58 @@ final class TrackingMacroTests: XCTestCase {
     }
   }
 
+  func test_primitive() {
+    
+    assertMacro {
+      """
+      @Tracking
+      struct MyState {
+      
+        var int: Int
+      
+        var int_literalOptional: Int?
+      
+        var int_literalOptional_literalOptional: Int??
+      
+        var int_typedOptinal: Optional<Int>
+      
+        var int_typedOptional_typedOptional: Optional<Optional<Int>>
+      
+        var int_typedOptional_literalOptional: Optional<Int?>
+      }
+      """
+    } expansion: {
+      """
+      struct MyState {
+        @PrimitiveTrackingProperty
+
+        var int: Int
+        @PrimitiveTrackingProperty
+
+        var int_literalOptional: Int?
+        @PrimitiveTrackingProperty
+
+        var int_literalOptional_literalOptional: Int??
+        @PrimitiveTrackingProperty
+
+        var int_typedOptinal: Optional<Int>
+        @PrimitiveTrackingProperty
+
+        var int_typedOptional_typedOptional: Optional<Optional<Int>>
+        @PrimitiveTrackingProperty
+
+        var int_typedOptional_literalOptional: Optional<Int?>
+
+        internal var _tracking_context: _TrackingContext = .init()
+      }
+
+      extension MyState: TrackingObject {
+      }
+      """
+    }
+    
+  }
+  
   func test_array_dictionary() {
     assertMacro {
       """