Serialize Reference isn't working with Custom Attributes (for example - Range)

I am trying to combine serialize reference with my custom attribute but it ignores and use default drawer.
I tried to setup with Int property and Range attributes to see if the problem on my custom attribute implementation but it is not.

Sample script:

Code (CSharp):

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using UnityEngine;
5. #if UNITY_EDITOR
6. using UnityEditor;
7.  
8. #endif
9.  
10.  
11. public interface IFruit
12. {
13. }
14.  
15. public abstract class Fruit : IFruit
16. {
17.     public string fruitName;
18. }
19.  
20. [Serializable]
21. public class Orange : Fruit
22. {
23.     public enum OrangeType
24.     {
25.         Valencia,
26.         Blood,
27.         Jaffa
28.     }
29.  
30.     [SerializeField] private OrangeType orangeType = default;
31. }
32.  
33. [Serializable]
34. public class Apple : Fruit
35. {
36.     public enum AppleType
37.     {
38.         Gala,
39.         GrannySmith,
40.         RedDelicious
41.     }
42.  
43.     [SerializeField] private AppleType appleType = default;
44.  
45.     [SerializeField] [Range(0, 9)] private int count;
46. }
47.  
48. public class InspectorTesting : MonoBehaviour
49. {
50.     [SerializeReference] public List<IFruit> fruits = new List<IFruit>();
51. }
52.  
53. #if UNITY_EDITOR
54.  
55. [CustomEditor(typeof(InspectorTesting))]
56. public class InspectorTestingEditor : Editor
57. {
58.     private InspectorTesting source;
59.     private SerializedObject sourceRef;
60.     private SerializedProperty fruits;
61.  
62.     private int dropDownSelection;
63.     private Type[] types;
64.     private string[] names;
65.  
66.     private void OnEnable()
67.     {
68.         source = (InspectorTesting) target;
69.         sourceRef = serializedObject;
70.  
71.         GetProperties();
72.     }
73.  
74.     void GetProperties()
75.     {
76.         types = GetAllOfInterface(typeof(Fruit));
77.         names = new string[1];
78.         names[0] = "Add A Fruit!";
79.         names = names.Concat(GetAllOfInterfaceNames(typeof(Fruit))).ToArray();
80.         fruits = sourceRef.FindProperty("fruits");
81.     }
82.  
83.     public override void OnInspectorGUI()
84.     {
85.         DisplayProperties();
86.         sourceRef.ApplyModifiedProperties();
87.     }
88.  
89.     void DisplayProperties()
90.     {
91.         dropDownSelection = EditorGUILayout.Popup(dropDownSelection, names);
92.         if (dropDownSelection != 0)
93.         {
94.             var fruit = Activator.CreateInstance(types[dropDownSelection - 1]) as Fruit;
95.             fruit.fruitName = fruit.GetType().Name;
96.             source.fruits.Add(fruit);
97.             dropDownSelection = 0;
98.         }
99.  
100.         EditorGUILayout.PropertyField(fruits, true);
101.     }
102.  
103.     string[] GetAllOfInterfaceNames(Type _interfaceType)
104.     {
105.         return GetAllOfInterface(_interfaceType)
106.             .Select(x => x.Name)
107.             .ToArray();
108.     }
109.  
110.     Type[] GetAllOfInterface(Type _interfaceType)
111.     {
112.         return AppDomain.CurrentDomain.GetAssemblies()
113.             .SelectMany(s => s.GetTypes())
114.             .Where(x => _interfaceType.IsAssignableFrom(x) && x != _interfaceType && !x.IsAbstract)
115.             .OrderBy(x => x.Name)
116.             .ToArray();
117.     }
118. }
119.  
120. #endif

 

Same issue here. I think SerializeReference doesn't work with polymorhisim on the inspector.
Unity 2019.3.0b11.