From c41133728d1a4197b8d0a366854b73d161788d20 Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Fri, 19 Jun 2015 15:54:13 +0000
Subject: [PATCH] Fix PR#18843. Thanks to Howard for the fix

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@240136 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/memory                                               | 5 ++++-
 .../util.smartptr.enab/enable_shared_from_this.pass.cpp      | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/memory b/include/memory
index 03897b1c..4c3a18c9 100644
--- a/include/memory
+++ b/include/memory
@@ -4073,7 +4073,10 @@ private:
         __enable_weak_this(const enable_shared_from_this<_Yp>* __e) _NOEXCEPT
         {
             if (__e)
-                __e->__weak_this_ = *this;
+            {
+                __e->__weak_this_.__ptr_ = const_cast<_Yp*>(static_cast<const _Yp*>(__e));
+                __e->__weak_this_.__cntrl_ = __cntrl_;
+            }
         }
 
     _LIBCPP_INLINE_VISIBILITY
diff --git a/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp b/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
index 58686d68..77af13fa 100644
--- a/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
+++ b/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
@@ -34,6 +34,10 @@ struct Z : Y {};
 
 int main()
 {
+    {  // https://llvm.org/bugs/show_bug.cgi?id=18843
+    std::shared_ptr<T const> t1(new T);
+    std::shared_ptr<T const> t2(std::make_shared<T>());
+    }
     {
     std::shared_ptr<Y> p(new Z);
     std::shared_ptr<T> q = p->shared_from_this();