diff --git a/libcxx/include/memory b/libcxx/include/memory
--- a/libcxx/include/memory
+++ b/libcxx/include/memory
@@ -3585,7 +3585,7 @@
                        _NOEXCEPT;
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
     template<class _Yp> explicit shared_ptr(const weak_ptr<_Yp>& __r,
-                   typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type= __nat());
+                   typename enable_if<__compatible_with<_Yp, _Tp>::value, __nat>::type= __nat());
 #if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     template<class _Yp>
@@ -4529,7 +4529,12 @@
 class _LIBCPP_TEMPLATE_VIS weak_ptr
 {
 public:
+#if _LIBCPP_STD_VER > 14
+    typedef remove_extent_t<_Tp> element_type;
+#else
     typedef _Tp element_type;
+#endif
+
 private:
     element_type*        __ptr_;
     __shared_weak_count* __cntrl_;
@@ -4560,7 +4565,7 @@
     template<class _Yp>
         typename enable_if
         <
-            is_convertible<_Yp*, element_type*>::value,
+            __compatible_with<_Yp, _Tp>::value,
             weak_ptr&
         >::type
         _LIBCPP_INLINE_VISIBILITY
@@ -4573,7 +4578,7 @@
     template<class _Yp>
         typename enable_if
         <
-            is_convertible<_Yp*, element_type*>::value,
+            __compatible_with<_Yp, _Tp>::value,
             weak_ptr&
         >::type
         _LIBCPP_INLINE_VISIBILITY
@@ -4584,7 +4589,7 @@
     template<class _Yp>
         typename enable_if
         <
-            is_convertible<_Yp*, element_type*>::value,
+            __compatible_with<_Yp, _Tp>::value,
             weak_ptr&
         >::type
         _LIBCPP_INLINE_VISIBILITY
@@ -4713,7 +4718,7 @@
 inline
 typename enable_if
 <
-    is_convertible<_Yp*, _Tp*>::value,
+    __compatible_with<_Yp, _Tp>::value,
     weak_ptr<_Tp>&
 >::type
 weak_ptr<_Tp>::operator=(weak_ptr<_Yp> const& __r) _NOEXCEPT
@@ -4738,7 +4743,7 @@
 inline
 typename enable_if
 <
-    is_convertible<_Yp*, _Tp*>::value,
+    __compatible_with<_Yp, _Tp>::value,
     weak_ptr<_Tp>&
 >::type
 weak_ptr<_Tp>::operator=(weak_ptr<_Yp>&& __r) _NOEXCEPT
@@ -4754,7 +4759,7 @@
 inline
 typename enable_if
 <
-    is_convertible<_Yp*, _Tp*>::value,
+    __compatible_with<_Yp, _Tp>::value,
     weak_ptr<_Tp>&
 >::type
 weak_ptr<_Tp>::operator=(shared_ptr<_Yp> const& __r) _NOEXCEPT
@@ -4791,7 +4796,7 @@
 template<class _Tp>
 template<class _Yp>
 shared_ptr<_Tp>::shared_ptr(const weak_ptr<_Yp>& __r,
-                            typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type)
+                            typename enable_if<__compatible_with<_Yp, _Tp>::value, __nat>::type)
     : __ptr_(__r.__ptr_),
       __cntrl_(__r.__cntrl_ ? __r.__cntrl_->lock() : __r.__cntrl_)
 {
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
@@ -82,5 +82,47 @@
     assert(A::count == 0);
 #endif
 
+#if STD_TEST_VERSION > 14
+    {
+        std::shared_ptr<A[4]> sp0(new A[4]);
+        std::weak_ptr<A[4]> wp(sp0);
+        std::shared_ptr<A[4]> sp(wp);
+        assert(sp.use_count() == 2);
+        assert(sp.get() == sp0.get());
+        assert(A::count == 4);
+    }
+    assert(A::count == 0);
+
+    {
+        std::shared_ptr<A[4]> sp0(new A[4]);
+        std::weak_ptr<A[4]> wp(sp0);
+        std::shared_ptr<B[4]> sp(wp);
+        assert(sp.use_count() == 2);
+        assert(sp.get() == sp0.get());
+        assert(A::count == 4);
+    }
+    assert(A::count == 0);
+
+    {
+        std::shared_ptr<A[4]> sp0(new A[4]);
+        std::weak_ptr<A[4]> wp(sp0);
+        std::shared_ptr<A> sp(wp);
+        assert(sp.use_count() == 2);
+        assert(sp.get() == sp0.get());
+        assert(A::count == 4);
+    }
+    assert(A::count == 0);
+
+    {
+        std::shared_ptr<A[4]> sp0(new A[4]);
+        std::weak_ptr<A[4]> wp(sp0);
+        std::shared_ptr<B> sp(wp);
+        assert(sp.use_count() == 2);
+        assert(sp.get() == sp0.get());
+        assert(A::count == 4);
+    }
+    assert(A::count == 0);
+#endif // STD_TEST_VERSION > 14
+
   return 0;
 }
diff --git a/libcxx/www/cxx1z_status.html b/libcxx/www/cxx1z_status.html
--- a/libcxx/www/cxx1z_status.html
+++ b/libcxx/www/cxx1z_status.html
@@ -481,7 +481,7 @@
 	<tr><td><a href="https://wg21.link/LWG2873">2873</a></td><td>Add noexcept to several shared_ptr related functions</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2874">2874</a></td><td>Constructor shared_ptr::shared_ptr(Y*) should be constrained</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="https://wg21.link/LWG2875">2875</a></td><td>shared_ptr::shared_ptr(Y*, D, [&hellip;]) constructors should be constrained</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="https://wg21.link/LWG2876">2876</a></td><td>shared_ptr::shared_ptr(const weak_ptr&lt;Y&gt;&amp;) constructor should be constrained</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="https://wg21.link/LWG2876">2876</a></td><td>shared_ptr::shared_ptr(const weak_ptr&lt;Y&gt;&amp;) constructor should be constrained</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2878">2878</a></td><td>Missing DefaultConstructible requirement for istream_iterator default constructor</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2890">2890</a></td><td>The definition of 'object state' applies only to class types</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2900">2900</a></td><td>The copy and move constructors of optional are not constexpr</td><td>Kona</td><td>Complete</td></tr>