From 220e83ca0af3ae16d46884456864c9d4daf48eb0 Mon Sep 17 00:00:00 2001
From: ncguilbeault <ncguilbeault@gmail.com>
Date: Thu, 13 Aug 2026 09:20:39 +0100
Subject: [PATCH 1/2] Refactor EnumerateTypeHierarchy for nested type traversal

---
 .../ParsingConfigHelper.cs                    | 27 ++++++++++++-------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/Bonsai.Scripting.Expressions/ParsingConfigHelper.cs b/src/Bonsai.Scripting.Expressions/ParsingConfigHelper.cs
index 0929d2e..5dbbecb 100644
--- a/src/Bonsai.Scripting.Expressions/ParsingConfigHelper.cs
+++ b/src/Bonsai.Scripting.Expressions/ParsingConfigHelper.cs
@@ -24,16 +24,25 @@ static IDynamicLinqCustomTypeProvider CreateCustomTypeProvider(ParsingConfig con
 
         static IEnumerable<Type> EnumerateTypeHierarchy(Type type)
         {
-            var interfaces = type.GetInterfaces();
-            for (int i = 0; i < interfaces.Length; i++)
+            var visited = new HashSet<Type>();
+            var stack = new Stack<Type>();
+            stack.Push(type);
+            while (stack.Count > 0)
             {
-                yield return interfaces[i];
-            }
-
-            while (type is not null)
-            {
-                yield return type;
-                type = type.BaseType;
+                var current = stack.Pop();
+                if (!visited.Add(current)) continue;
+                foreach (var interfaceType in current.GetInterfaces())
+                {
+                    yield return interfaceType;
+                }
+                for (var baseType = current; baseType is not null; baseType = baseType.BaseType)
+                {
+                    yield return baseType;
+                }
+                foreach (var property in current.GetProperties())
+                {
+                    stack.Push(property.PropertyType);
+                }
             }
         }
 

From 0af759619872bc4cc10e5e9f2d9304cff709188a Mon Sep 17 00:00:00 2001
From: ncguilbeault <ncguilbeault@gmail.com>
Date: Fri, 14 Aug 2026 13:37:43 +0100
Subject: [PATCH 2/2] Add tests for nested and transitive nested property types

---
 .../ExpressionScriptingTests.cs               | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/Bonsai.Scripting.Expressions.Tests/ExpressionScriptingTests.cs b/src/Bonsai.Scripting.Expressions.Tests/ExpressionScriptingTests.cs
index 2d41330..6a8abfd 100644
--- a/src/Bonsai.Scripting.Expressions.Tests/ExpressionScriptingTests.cs
+++ b/src/Bonsai.Scripting.Expressions.Tests/ExpressionScriptingTests.cs
@@ -70,6 +70,23 @@ public Task TestCasingCompatibility<TSource, TResult>(string expression, TSource
             return AssertExpressionTransform(expression, value, expected);
         }
 
+        [TestMethod]
+        [DataRow("it.Value == NestedEnum.B", true)]
+        [DataRow("NestedEnum(it.Value + 1)", NestedEnum.C)]
+        public Task TestNestedPropertyType<TResult>(string expression, TResult expected)
+        {
+            return AssertExpressionTransform(expression, new NestedElement { Value = NestedEnum.B }, expected);
+        }
+
+        [TestMethod]
+        [DataRow("it.Element.Value == NestedEnum.B", true)]
+        [DataRow("NestedElement(object(it.Element)).Value", NestedEnum.B)]
+        public Task TestTransitiveNestedPropertyType<TResult>(string expression, TResult expected)
+        {
+            var value = new NestedContainer { Element = new NestedElement { Value = NestedEnum.B } };
+            return AssertExpressionTransform(expression, value, expected);
+        }
+
         [TestMethod]
         [DataRow("")]
         [DataRow("string(it)")]
@@ -79,6 +96,18 @@ public Task TestInvalidExpression(string expression)
                 AssertExpressionTransform(expression, 42, (object)null));
         }
 
+        public enum NestedEnum { A, B, C }
+
+        public class NestedElement
+        {
+            public NestedEnum Value { get; set; }
+        }
+
+        public class NestedContainer
+        {
+            public NestedElement Element { get; set; }
+        }
+
         class Return<TValue>(TValue value) : Source<TValue>
         {
             public TValue Value { get; } = value;