slots_passing

#include <QObject>
#include <QTcpServer>
#include <QTcpSocket>

class SomeClass : public QObject {
  Q_OBJECT

    using slotMethod_t = void (SomeClass::*)();
public:
    explicit SomeClass(QObject* parent = nullptr) : QObject(parent), server(new TcpServer(this)) {
       connect(server, &QTcpServer::newConnection, this, replaceConnection(server, socket, &SomeClass::someSlot));
    }

public slots:
     void someSlot() {
      // read data from socket.
     }

std::function<void()> replaceConnection(
    QTcpServer* server_, QTcpSocket* socket_, slotMethod_t slot) {
    if (socket) {
        socket_->close();
        delete socket_;
    }
    return [&] {
        socket_ = server_->nextPendingConnection();
        connect(socket_, &QAbstractSocket::readyRead, this, slot);
    };
}

    QTcpServer* server;
    QTcpSocket* socket
};