Patched fatal flaw with property setter.

Turns out the property setter was failing to cover inheritance, so referent properties were being corrupted in the process. This should now be fixed.

I've also deprecated IsA<T>() in favor of using C#'s own `is` operator and stopped locking the parent of service classes to avoid saving issues.

BinaryFormat/Chunks/PRNT.cs

@@ -27,7 +27,6 @@ namespace RobloxFiles.BinaryFormat.Chunks
 
                 Instance child = file.Instances[childId];
                 child.Parent = (parentId >= 0 ? file.Instances[parentId] : file);
-                child.ParentLocked = child.IsService;
             }
         }
 

BinaryFormat/Chunks/PROP.cs

@@ -362,7 +362,12 @@ namespace RobloxFiles.BinaryFormat.Chunks
                     readProperties(i =>
                     {
                         int instId = instIds[i];
-                        return instId >= 0 ? file.Instances[instId] : null;
+                        Instance result = null;
+
+                        if (instId >= 0)
+                            result = file.Instances[instId];
+
+                        return result;
                     });
 
                     break;

Tree/Instance.cs

@@ -53,11 +53,8 @@ namespace RobloxFiles
         /// <summary>Indicates whether this Instance is a Service.</summary>
         public bool IsService { get; internal set; }
 
-        /// <summary>Raw list of CollectionService tags assigned to this Instance.</summary>
-        private List<string> RawTags = new List<string>();
-
         /// <summary>A list of CollectionService tags assigned to this Instance.</summary>
-        public List<string> Tags => RawTags;
+        public List<string> Tags { get; } = new List<string>();
 
         /// <summary>The attributes defined for this Instance.</summary>
         public Attributes Attributes { get; private set; }
@@ -144,6 +141,7 @@ namespace RobloxFiles
         /// <summary>
         /// Returns true if the provided instance inherits from the provided instance type.
         /// </summary>
+        [Obsolete("Use the `is` operator instead.")]
         public bool IsA<T>() where T : Instance
         {
             Type myType = GetType();
@@ -161,7 +159,7 @@ namespace RobloxFiles
         {
             T result = null;
 
-            if (IsA<T>())
+            if (this is T)
                 result = this as T;
 
             return result;
@@ -212,7 +210,7 @@ namespace RobloxFiles
         public T[] GetChildrenOfType<T>() where T : Instance
         {
             T[] ofType = GetChildren()
-                .Where(child => child.IsA<T>())
+                .Where(child => child is T)
                 .Cast<T>()
                 .ToArray();
 
@@ -224,7 +222,7 @@ namespace RobloxFiles
         /// </summary>
         public Instance[] GetDescendants()
         {
-            List<Instance> results = new List<Instance>();
+            var results = new List<Instance>();
 
             foreach (Instance child in Children)
             {
@@ -245,7 +243,7 @@ namespace RobloxFiles
         public T[] GetDescendantsOfType<T>() where T : Instance
         {
             T[] ofType = GetDescendants()
-                .Where(desc => desc.IsA<T>())
+                .Where(desc => desc is T)
                 .Cast<T>()
                 .ToArray();
 
@@ -361,9 +359,9 @@ namespace RobloxFiles
 
             while (check != null)
             {
-                if (check.IsA<T>())
+                if (check is T)
                 {
-                    ancestor = (T)check;
+                    ancestor = check as T;
                     break;
                 }
 
@@ -415,30 +413,26 @@ namespace RobloxFiles
         public T FindFirstChildWhichIsA<T>(bool recursive = false) where T : Instance
         {
             var query = Children
-                .Where(child => child.IsA<T>())
+                .Where(child => child is T)
                 .Cast<T>();
 
-            T result = null;
-
             if (query.Any())
-            {
-                result = query.First();
-            }
-            else if (recursive)
+                return query.First();
+            
+            if (recursive)
             {
                 foreach (Instance child in Children)
                 {
                     T found = child.FindFirstChildWhichIsA<T>(true);
 
-                    if (found != null)
-                    {
-                        result = found;
-                        break;
-                    }
+                    if (found == null)
+                        continue;
+
+                    return found;
                 }
             }
 
-            return result;
+            return null;
         }
 
         /// <summary>
@@ -539,6 +533,7 @@ namespace RobloxFiles
                     {
                         case "String":
                         case "Double":
+                        case "Int64":
                             xmlToken = xmlToken.ToLowerInvariant();
                             break;
                         case "Boolean":
@@ -550,9 +545,6 @@ namespace RobloxFiles
                         case "Int32":
                             xmlToken = "int";
                             break;
-                        case "Int64":
-                            xmlToken = "int64";
-                            break;
                         case "Rect":
                             xmlToken = "Rect2D";
                             break;
@@ -564,7 +556,7 @@ namespace RobloxFiles
 
                     if (!props.ContainsKey(fieldName))
                     {
-                        Property newProp = new Property()
+                        var newProp = new Property()
                         {
                             Value = field.GetValue(this),
                             XmlToken = xmlToken,

Tree/Property.cs

@@ -228,7 +228,7 @@ namespace RobloxFiles
                             var valueType = value?.GetType();
                             Type memberType = member.MemberType;
                             
-                            if (memberType == valueType || value == null)
+                            if (value == null || memberType.IsAssignableFrom(valueType))
                             {
                                 try
                                 {