From 4d01e548652cad1505a397dafaa96caa757a6c41 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Fri, 18 Apr 2025 10:36:08 -0400
Subject: [PATCH] LibGC: Allow move-assigning RootVector instances

Rule of 5 - we were missing a move-assignment operator, thus all move
assignments resulted in a copy.
---
 Libraries/LibGC/RootVector.cpp | 13 ++++++-------
 Libraries/LibGC/RootVector.h   | 20 ++++++++++++++++----
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/Libraries/LibGC/RootVector.cpp b/Libraries/LibGC/RootVector.cpp
index 7676c170bf7..47b7a262792 100644
--- a/Libraries/LibGC/RootVector.cpp
+++ b/Libraries/LibGC/RootVector.cpp
@@ -21,16 +21,15 @@ RootVectorBase::~RootVectorBase()
     m_heap->did_destroy_root_vector({}, *this);
 }
 
-RootVectorBase& RootVectorBase::operator=(RootVectorBase const& other)
+void RootVectorBase::assign_heap(Heap* heap)
 {
-    if (m_heap != other.m_heap) {
-        m_heap = other.m_heap;
+    if (m_heap == heap)
+        return;
 
-        // NOTE: IntrusiveList will remove this RootVectorBase from the old heap it was part of.
-        m_heap->did_create_root_vector({}, *this);
-    }
+    m_heap = heap;
 
-    return *this;
+    // NOTE: IntrusiveList will remove this RootVectorBase from the old heap it was part of.
+    m_heap->did_create_root_vector({}, *this);
 }
 
 }
diff --git a/Libraries/LibGC/RootVector.h b/Libraries/LibGC/RootVector.h
index 9c7b7b3cf36..a448ea54e6b 100644
--- a/Libraries/LibGC/RootVector.h
+++ b/Libraries/LibGC/RootVector.h
@@ -24,7 +24,7 @@ protected:
     explicit RootVectorBase(Heap&);
     ~RootVectorBase();
 
-    RootVectorBase& operator=(RootVectorBase const&);
+    void assign_heap(Heap*);
 
     Heap* m_heap { nullptr };
     IntrusiveListNode<RootVectorBase> m_list_node;
@@ -38,6 +38,8 @@ class RootVector final
     : public RootVectorBase
     , public Vector<T, inline_capacity> {
 
+    using VectorBase = Vector<T, inline_capacity>;
+
 public:
     explicit RootVector(Heap& heap)
         : RootVectorBase(heap)
@@ -60,14 +62,24 @@ public:
 
     RootVector(RootVector&& other)
         : RootVectorBase(*other.m_heap)
-        , Vector<T, inline_capacity>(move(static_cast<Vector<T, inline_capacity>&>(other)))
+        , VectorBase(move(static_cast<VectorBase&>(other)))
     {
     }
 
     RootVector& operator=(RootVector const& other)
     {
-        Vector<T, inline_capacity>::operator=(other);
-        RootVectorBase::operator=(other);
+        if (&other == this)
+            return *this;
+
+        assign_heap(other.m_heap);
+        VectorBase::operator=(other);
+        return *this;
+    }
+
+    RootVector& operator=(RootVector&& other)
+    {
+        assign_heap(other.m_heap);
+        VectorBase::operator=(move(static_cast<VectorBase&>(other)));
         return *this;
     }