From fd5136a1ab4d2b54ce8db80bf3ed93147a654d86 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Mon, 11 Feb 2019 12:44:01 +0100
Subject: [PATCH] AK: Oops, the optimization in Vector::append(Vector&&) was
 broken.

It forgot to clear out the moved-from vector. It's easy to see where this bug
came from: I assumed m_impl was an OwnPtr. It would be comfy if move() on some
arbitrary T* would also null it out but alas that's not how things work.
---
 AK/Vector.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/AK/Vector.h b/AK/Vector.h
index 2870f90671..4e6ae11879 100644
--- a/AK/Vector.h
+++ b/AK/Vector.h
@@ -173,7 +173,8 @@ public:
     void append(Vector<T>&& other)
     {
         if (!m_impl) {
-            m_impl = move(other.m_impl);
+            m_impl = other.m_impl;
+            other.m_impl = nullptr;
             return;
         }
         Vector<T> tmp = move(other);