类型擦除类(非模板抽象基类和模板派生类)：

#include <type_traits>
#include <mutex>
#include <chrono>
#include <iostream>

namespace detail {

    struct locker_unlocker_base {
        virtual void lock() = 0;
        virtual void unlock() = 0;
    };

    template<class Mutex>
    struct locker_unlocker : public locker_unlocker_base {
        locker_unlocker(Mutex &m) : m_m{&m} {}
        virtual void lock() { m_m->lock(); }
        virtual void unlock() { m_m->unlock(); }
        Mutex *m_m;
    };
}

现在te_lock_guard，类型擦除锁保护，只需在构造时(没有动态内存分配)将正确类型的对象放置--新闻：

class te_lock_guard {
public:
    template<class Mutex>
    te_lock_guard(Mutex &m) {
        new (&m_buf) detail::locker_unlocker<Mutex>(m);
        reinterpret_cast<detail::locker_unlocker_base *>(&m_buf)->lock();
    }
    ~te_lock_guard() {
        reinterpret_cast<detail::locker_unlocker_base *>(&m_buf)->unlock();
    }

private:
    std::aligned_storage<sizeof(detail::locker_unlocker<std::mutex>), alignof(detail::locker_unlocker<std::mutex>)>::type m_buf;
};

我检查了性能与标准库的类：

int main() {
    constexpr std::size_t num{999999};
    {
        std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
        for(size_t i = 0; i < num; ++i) {
            std::mutex m;
            te_lock_guard l(m);
        }
        std::chrono::steady_clock::time_point end= std::chrono::steady_clock::now();
        std::cout << std::chrono::duration_cast<std::chrono::microseconds>(end - begin).count() << std::endl;
    }
    {
        std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
        for(size_t i = 0; i < num; ++i) {
            std::mutex m;
            std::unique_lock<std::mutex> l(m);
        }
        std::chrono::steady_clock::time_point end= std::chrono::steady_clock::now();
        std::cout << std::chrono::duration_cast<std::chrono::microseconds>(end - begin).count() << std::endl;
    }
}