From 66d1050af64c175f232d5bcb643741662fa1477f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steven=20Dee=20=28J=C5=8Dshin=29?= <git@wholezero.org>
Date: Thu, 17 Apr 2025 14:01:20 -0700
Subject: [PATCH] Correctly implement weak_ptr assignment/copy/moves (#1399)

---
 ctl/shared_ptr.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/ctl/shared_ptr.h b/ctl/shared_ptr.h
index c387f2198..78cf4aeb2 100644
--- a/ctl/shared_ptr.h
+++ b/ctl/shared_ptr.h
@@ -382,6 +382,34 @@ class weak_ptr
             rc->keep_weak();
     }
 
+    weak_ptr(weak_ptr const& r) noexcept : p(r.p), rc(r.rc)
+    {
+        if (rc)
+            rc->keep_weak();
+    }
+
+    template<typename U>
+        requires __::shared_ptr_compatible<T, U>
+    weak_ptr(weak_ptr<U> const& r) noexcept : p(r.p), rc(r.rc)
+    {
+        if (rc)
+            rc->keep_weak();
+    }
+
+    weak_ptr(weak_ptr&& r) noexcept : p(r.p), rc(r.rc)
+    {
+        r.p = nullptr;
+        r.rc = nullptr;
+    }
+
+    template<typename U>
+        requires __::shared_ptr_compatible<T, U>
+    weak_ptr(weak_ptr<U>&& r) noexcept : p(r.p), rc(r.rc)
+    {
+        r.p = nullptr;
+        r.rc = nullptr;
+    }
+
     ~weak_ptr()
     {
         if (rc)
@@ -410,6 +438,12 @@ class weak_ptr
         swap(rc, r.rc);
     }
 
+    weak_ptr& operator=(weak_ptr r) noexcept
+    {
+        swap(r);
+        return *this;
+    }
+
     shared_ptr<T> lock() const noexcept
     {
         if (expired())