note: cast from 'void *' is not allowed in a constant expression because the pointed object type 'std::__tree_node<std::__value_type<int, double>, min_pointer<void>>' is not similar to the target type 'std::__tree_node_base<min_pointer<void>>'

Author: vinay-deshmukh

libcxx/include/__tree

@@ -1270,7 +1270,7 @@ private:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 __node_holder __construct_node(_Args&&... __args);
 
   // TODO: Make this _LIBCPP_HIDE_FROM_ABI
-  _LIBCPP_HIDDEN void destroy(__node_pointer __nd) _NOEXCEPT;
+  _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX26 void destroy(__node_pointer __nd) _NOEXCEPT;
 
   _LIBCPP_HIDE_FROM_ABI void __move_assign(__tree& __t, false_type);
   _LIBCPP_HIDE_FROM_ABI void __move_assign(__tree& __t, true_type) _NOEXCEPT_(
@@ -1540,7 +1540,7 @@ _LIBCPP_CONSTEXPR_SINCE_CXX26 __tree<_Tp, _Compare, _Allocator>::~__tree() {
 }
 
 template <class _Tp, class _Compare, class _Allocator>
-void __tree<_Tp, _Compare, _Allocator>::destroy(__node_pointer __nd) _NOEXCEPT {
+_LIBCPP_CONSTEXPR_SINCE_CXX26 void __tree<_Tp, _Compare, _Allocator>::destroy(__node_pointer __nd) _NOEXCEPT {
   if (__nd != nullptr) {
     destroy(static_cast<__node_pointer>(__nd->__left_));
     destroy(static_cast<__node_pointer>(__nd->__right_));

libcxx/test/std/containers/associative/map/map.access/at.pass.cpp

@@ -75,13 +75,15 @@ TEST_CONSTEXPR_CXX26 bool test() {
     assert(m.at(3) == 3.5);
     assert(m.at(4) == 4.5);
     assert(m.at(5) == 5.5);
-#ifndef TEST_HAS_NO_EXCEPTIONS
+// throwing is not allowed in constexpr
+#if TEST_STD_VER < 26
     try {
       TEST_IGNORE_NODISCARD m.at(6);
       assert(false);
     } catch (std::out_of_range&) {
     }
 #endif
+
     assert(m.at(7) == 7.5);
     assert(m.at(8) == 8.5);
     assert(m.size() == 7);