compile error happen when I use c++ template. it is from a third part library. there is a template class case_wrapper_base, when I create a instance with the type int, there will be compile error, complaining that const type can not use default initialization. template <class CT> class case_wrapper_base { public: explicit case_wrapper_base(const CT& v) : check(v), default_step(nullptr) {} case_wrapper_base& add_entry(const case_instruction& lambda_holder) { steps.push_back(&lambda_holder); return *this; } case_wrapper_base& add_default(const case_instruction& lambda_holder) { default_step = &lambda_holder; return *this; } case_wrapper_base& join() { return *this; } void run() const { auto it = steps.begin(); while(it != steps.end()) { bool increased = false; // error happens due to the two different type here if(dynamic_cast<const branch<CT>*>(*it) || dynamic_cast<const branch<const CT>*>(*it)) // do something. not important } the definition of class branch is template<class CT> class branch final : public case_instruction { public: template<class T> branch(T lambda) {condition.reset(new any_functor<T>(lambda));} bool equals(const base_rvholder& rv, CT lv) const { return rv.equals(lv); } virtual next_step execute(const base_rvholder& against) const override { // there is compile error here. Default initialization of an object of const type 'const int'. I know it is because the type of `CT` become `const int`. but why there is no error when build with Xcode15. can I make it no error by adding some settings in Xcode16? CT retv; condition->run( const_cast<void*>(reinterpret_cast<const void*>(&retv) ) ); return equals(against,retv) ? next_step::ns_done : next_step::ns_continue; } private: std::unique_ptr<any_functor_base> condition; }; @DTS Engineer appreciate your reply.

I see this issue is not resolved in Xcode16 Beta 2 unfortunately. Hope it can be resolved in next version. Some errors are from code in third part libraries and there is no way to change them.