Some small refactoring.

src/Arch/Core/Archetype.cs

@@ -167,7 +167,16 @@ internal Archetype(ComponentType[] types)
     internal int[] LookupArray
     {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        get => _componentIdToArrayIndex;
+        get
+        {
+            int[] managedArray = new int[_componentIdToArrayIndex.Length];
+            for (int i = 0; i < _componentIdToArrayIndex.Length; i++)
+            {
+                managedArray[i] = _componentIdToArrayIndex[i]; 
+            }
+
+            return managedArray;
+        }
     }
 
     /// <summary>

src/Arch/Core/Extensions/Dangerous/DangerousChunkExtensions.cs

@@ -17,7 +17,13 @@ public static class DangerousChunkExtensions
     /// <returns></returns>
     public static Chunk CreateChunk(int capacity, int[] lookupArray, ComponentType[] types)
     {
-        return new Chunk(capacity, lookupArray, types);
+        var unsafeLookupArray = new UnsafeArray<int>(lookupArray.Length);
+        for (var index = 0; index < lookupArray.Length; index++)
+        {
+            unsafeLookupArray[index] = lookupArray[index];
+        }
+
+        return new Chunk(capacity, unsafeLookupArray, types);
     }
 
     /// <summary>

src/Arch/Core/Utils/CompileTimeStatics.cs

@@ -41,9 +41,10 @@ public readonly record struct ComponentType
     /// </summary>
     /// <param name="id">Its unique id.</param>
     /// <param name="type">Its type.</param>
+    /// <param name="isManaged">If the type is managed.</param>
     /// <param name="byteSize">Its size in bytes.</param>
     /// <param name="zeroSized">True if its zero sized ( empty struct).</param>
-    public ComponentType(int id, Type type, int byteSize, bool zeroSized)
+    public ComponentType(int id, Type type, bool isManaged, int byteSize, bool zeroSized)
     {
         Id = id;
         Type = type;
@@ -126,7 +127,7 @@ private static ComponentType Add(Type type, int typeSize)
         }
 
         // Register and assign component id
-        meta = new ComponentType(Size + 1, type, typeSize, type.GetFields().Length == 0);
+        meta = ToComponentType(type);
         _types.Add(type, meta);
 
         Size++;
@@ -144,7 +145,29 @@ public static ComponentType Add(ComponentType type)
     {
         return Add(type.Type, type.ByteSize);
     }
+
+    /// <summary>
+    ///     Adds a new component and registers it.
+    /// </summary>
+    /// <typeparam name="T">The generic type.</typeparam>
+    /// <returns>Its <see cref="ComponentType"/>.</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ComponentType Add<T>()
+    {
+        return Add(typeof(T), SizeOf<T>());
+    }
 
+    /// <summary>
+    ///     Adds a new component and registers it.
+    /// </summary>
+    /// <param name="type">Its <see cref="Type"/>.</param>
+    /// <returns>Its <see cref="ComponentType"/>.</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ComponentType Add(Type type)
+    {
+        return Add(type, SizeOf(type));
+    }
+
     /// <summary>
     ///     Converts a <see cref="Type"/> into a fitting <see cref="ComponentType"/>.
     /// </summary>
@@ -182,17 +205,6 @@ public static ComponentType ToComponentType(Type type)
         return new ComponentType(Size, type, managed, size, type.GetFields().Length == 0);
     }
 
-    /// <summary>
-    ///     Adds a new component and registers it.
-    /// </summary>
-    /// <param name="type">Its <see cref="Type"/>.</param>
-    /// <returns>Its <see cref="ComponentType"/>.</returns>
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static ComponentType Add(Type type)
-    {
-        return Add(type, SizeOf(type));
-    }
-
     // NOTE: Should this be `Contains` to follow other existing .NET APIs (ICollection<T>.Contains(T))?
     /// <summary>
     ///     Checks if a component is registered.
@@ -272,7 +284,7 @@ public static void Replace(Type oldType, Type newType, int newTypeSize)
             id = ++Size;
         }
 
-        _types.Add(newType, new ComponentType(id, newType, newTypeSize, newType.GetFields().Length == 0));
+        _types.Add(newType, new ComponentType(id, newType, oldComponentType.IsManaged, newTypeSize,newType.GetFields().Length == 0));
     }
 
     /// <summary>