From 04668106386c9b8ae9f62f56bef9378f2e1cb914 Mon Sep 17 00:00:00 2001
From: Sergey Bugaev <bugaevc@serenityos.org>
Date: Fri, 12 Jun 2020 16:30:30 +0300
Subject: [PATCH] AK: Ensure we never use OwnPtr<> with RefCounted types

---
 AK/NonnullOwnPtr.h |  2 ++
 AK/OwnPtr.h        |  4 +++-
 AK/RefCounted.h    | 10 ++++++++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/AK/NonnullOwnPtr.h b/AK/NonnullOwnPtr.h
index 622290578a2..a9dd0cc474d 100644
--- a/AK/NonnullOwnPtr.h
+++ b/AK/NonnullOwnPtr.h
@@ -28,6 +28,7 @@
 
 #include <AK/Assertions.h>
 #include <AK/LogStream.h>
+#include <AK/RefCounted.h>
 #include <AK/StdLibExtras.h>
 #include <AK/Traits.h>
 #include <AK/Types.h>
@@ -51,6 +52,7 @@ public:
     NonnullOwnPtr(AdoptTag, T& ptr)
         : m_ptr(&ptr)
     {
+        static_assert(!is_ref_counted((const T*)nullptr), "Use RefPtr<> for RefCounted types");
     }
     NonnullOwnPtr(NonnullOwnPtr&& other)
         : m_ptr(other.leak_ptr())
diff --git a/AK/OwnPtr.h b/AK/OwnPtr.h
index ed351be0600..2ece450e81d 100644
--- a/AK/OwnPtr.h
+++ b/AK/OwnPtr.h
@@ -27,16 +27,18 @@
 #pragma once
 
 #include <AK/NonnullOwnPtr.h>
+#include <AK/RefCounted.h>
 
 namespace AK {
 
 template<typename T>
 class OwnPtr {
 public:
-    OwnPtr() {}
+    OwnPtr() { }
     explicit OwnPtr(T* ptr)
         : m_ptr(ptr)
     {
+        static_assert(!is_ref_counted((const T*)nullptr), "Use RefPtr<> for RefCounted types");
     }
     OwnPtr(OwnPtr&& other)
         : m_ptr(other.leak_ptr())
diff --git a/AK/RefCounted.h b/AK/RefCounted.h
index 361e6012861..98049405475 100644
--- a/AK/RefCounted.h
+++ b/AK/RefCounted.h
@@ -100,6 +100,16 @@ public:
     }
 };
 
+static constexpr bool is_ref_counted(const RefCountedBase*)
+{
+    return true;
+}
+
+static constexpr bool is_ref_counted(...)
+{
+    return false;
+}
+
 }
 
 using AK::RefCounted;