VS2022 C++20环境下自定义forward_iterator无法通过static_assert验证的问题求助

我最近在VS2022里基于C20标准实现自定义容器和迭代器，完全严格照着《Template Metaprogramming with C》（Marius Bancila著）里的API示例来写的，结果碰到了一个搞不懂的问题，想请大家帮忙分析下原因，或者给个修复思路。

我的代码结构大概是这样：

• 定义了模板类template <typename Value, typename Key = std::string> class my_container
• 配套的迭代器类template<typename Value, typename Key> class my_iterator，按照forward iterator的要求来设计

我想用static_assert验证这个迭代器是否符合标准：

static_assert(std::forward_iterator<my_iterator<int, std::string>>);

结果验证失败了，就连更基础的input iterator断言也通不过：

static_assert(std::input_iterator<my_iterator<int, std::string>>);

下面是完整的编译错误信息：

Build started at 16:36...
1>------ Build started: Project: TestForwardIteratorConsole, Configuration: Debug x64 ------
1>TestForwardIteratorConsole.cpp
1> ...\TestForwardIteratorConsole\TestForwardIteratorConsole.cpp(7,20): error C2607: static assertion failed
1> ...\TestForwardIteratorConsole\TestForwardIteratorConsole.cpp(7,20):
1> the concept 'std::input_iterator<my_iterator<int,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>' evaluated to false
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include\xutility(984,59):
1> the concept 'std::indirectly_readable<my_iterator<int,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>' evaluated to false
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include\xutility(898,31):
1> the concept 'std::_Indirectly_readable_impl<my_iterator<int,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>' evaluated to false
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include\xutility(891,21):
1> the concept 'std::same_as<const int&,int&>' evaluated to false
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include\xutility(891,21):
1> 'const int &' and 'int &' are different types
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include\xutility(891,11):
1> the expression was resolved to a call to 'my_iterator<int,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>::operator *'
1> ...\TestForwardIteratorConsole\MyIterator.h(174,21):
1> see declaration of 'my_iterator<int,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>::operator *'
1>Done building project "TestForwardIteratorConsole.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
========== Build completed at 16:36 and took 06,751 seconds ==========

让我困惑的是：如果把迭代器类里的operator*()注释掉，input iterator的断言居然能通过，但operator*()明明是forward iterator必须实现的方法啊。更奇怪的是，我去测试了书里配套的环形缓冲区迭代器示例代码，也碰到了完全一样的问题！这让我不禁怀疑是不是VS2022里的std::forward_iterator断言逻辑有问题？

之前有@康桓瑋和@Barry给了一些提示，指出了可能的问题点，但我还是没搞明白具体该怎么修复。

下面是我用来复现问题的简化测试代码（迭代器的operator*()在第180行被注释了）：

// MyIterator templates and declarations
#pragma once
#include <string>
#include <map>
#include <iterator>

template<typename Value, typename Key = std::string>
class my_container {
    // 容器实现（仅用于测试，无实际业务逻辑）
};

template<typename Value, typename Key>
class my_iterator {
public:
    using value_type = Value;
    using difference_type = std::ptrdiff_t;
    using pointer = Value*;
    using reference = Value&;
    using iterator_category = std::forward_iterator_tag;

    // 其他迭代器必需的方法实现（比如operator++、operator==等）

    // 注释掉这个operator*()，input_iterator断言能通过；放开则失败
    // reference operator*() {
    //     // 简化的返回逻辑
    //     return *some_pointer;
    // }
};

// 测试断言
static_assert(std::input_iterator<my_iterator<int, std::string>>);
static_assert(std::forward_iterator<my_iterator<int, std::string>>);

有没有大佬能帮我分析下问题出在哪，或者给个修复的方向？

内容来源于stack exchange