From 462b080bffd202b83b50b22dfd90e1b2f25ff07f Mon Sep 17 00:00:00 2001
From: Timofey Burak <timofey.burak@softeq.com>
Date: Mon, 17 Oct 2022 13:41:23 +0200
Subject: [PATCH] Conditional Assert to warn about compiler-generated targets

---
 Softeq.XToolkit.Common/Weak/WeakDelegate.cs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Softeq.XToolkit.Common/Weak/WeakDelegate.cs b/Softeq.XToolkit.Common/Weak/WeakDelegate.cs
index a52b890c3..90c0771cb 100644
--- a/Softeq.XToolkit.Common/Weak/WeakDelegate.cs
+++ b/Softeq.XToolkit.Common/Weak/WeakDelegate.cs
@@ -2,7 +2,9 @@
 // http://www.softeq.com
 
 using System;
+using System.Diagnostics;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
 
 namespace Softeq.XToolkit.Common.Weak
@@ -27,6 +29,7 @@ protected WeakDelegate(object? target, TDelegate @delegate)
                 return;
             }
 
+            AssertCompilerGeneratedTarget(@delegate);
             DelegateTargetReference = new WeakReference(@delegate.Target);
             if (!ReferenceEquals(@delegate.Target, target))
             {
@@ -137,5 +140,18 @@ protected T TryExecuteWeakDelegate<T>(params object?[] parameters)
                 ? DelegateTargetReference?.Target
                 : null;
         }
+
+        [Conditional("DEBUG")]
+        private static void AssertCompilerGeneratedTarget(TDelegate @delegate)
+        {
+            var isCompilerGenerated = @delegate.Target.GetType().GetCustomAttribute<CompilerGeneratedAttribute>() != null;
+            if (!isCompilerGenerated)
+            {
+                return;
+            }
+
+            Debug.WriteLine("WeakDelegate's target is compiler-generated, it might be garbage-collected");
+            Debug.WriteLine(Environment.StackTrace);
+        }
     }
 }