重写模板类中的虚函数时出错

我在重写纯虚拟函数[getContents()]时遇到问题: 我试图用派生类fpmessageImpl继承一个类fpmessage

然而,当我尝试实例化fpmessageImpl时,编译器报告它是虚拟的,因为getContents()是一个未实现的纯虚拟函数(尽管覆盖没有问题)。这里发生了什么,有没有办法解决? clang++错误报告的最后一部分:(fpmessagingSystemImpl中有问题的代码已移至MWE中的main)

src/fpmessagingsystemimpl.h:56:7: note: in instantiation of member function 'fp::utils::fpmessagingSystemImpl<fp::utils::fpMessagingDataStates::States>::send_message' requested here
      fpmessagingSystemImpl(std::map<MessageType,std::type_index> m) noexcept :
      ^
src/fpengineimpl.h:19:21: note: in instantiation of member function 'fp::utils::fpmessagingSystemImpl<fp::utils::fpMessagingDataStates::States>::fpmessagingSystemImpl' requested here
      msg_sys = new fp::utils::fpmessagingSystemImpl<fp::utils::fpMessagingDataStates::States>(ds.get_map());
                    ^
src/fpmessagingsystem.h:32:48: note: unimplemented pure virtual method 'getContents' in 'fpmessage'
      virtual std::tuple<MessageType,std::any> getContents() const noexcept = 0;

可复制示例: 问题似乎在于std::make_shared如何构造新的fpmessage(主要):

#include <memory>
#include <any>
#include <map>
#include <typeindex>

class fpMessagingDataStates {
public:
  enum class States{
    INIT
  };
  const std::map<fpMessagingDataStates::States,std::type_index> get_map() {
    return m;
  }
  fpMessagingDataStates(){
    m = std::map<fpMessagingDataStates::States,std::type_index>();
    m.emplace(std::make_pair(fpMessagingDataStates::States::INIT,std::type_index(typeid(std::wstring))));
  }
private:
  std::map<fpMessagingDataStates::States,std::type_index> m;
};

template<typename MessageType>
class fpmessage{
public:
  fpmessage(MessageType mt, std::any a) noexcept {};
  virtual bool validate_message (const std::map<MessageType,std::type_index>& map) const noexcept {return false;}
  virtual std::tuple<MessageType,std::any> getContents() const noexcept = 0;
  /*virtual ~fpmessage();*/
protected:
  fpmessage() {};
};

template<typename MessageType>
class fpmessageImpl : public fpmessage<MessageType>{
public:
  fpmessageImpl() = delete;
  fpmessageImpl(MessageType mt, std::any a) :
    t(mt),
    contents(a) {}
  // check stored message type against a map
  virtual bool validate_message(const std::map<MessageType,std::type_index>& map) const noexcept override{
    // check the expected message type against the actual type
    auto expected_type = map.find(t);
    return (expected_type->second == std::type_index(contents.type()));
  }
  virtual std::tuple<MessageType,std::any> getContents() const noexcept override {
    return std::make_tuple(t,contents);
  }
private:
  const MessageType t;
  const std::any contents;
};

int main(int argc, char** argv)
{
  std::wstring s = L"Engine Started";
  auto state = fpMessagingDataStates::States::INIT;
  auto m = fpmessageImpl<fpMessagingDataStates::States>(state, s);
  auto mess = std::make_shared<fpmessage<fpMessagingDataStates::States>>(m);
  return 0;
}