<deque>,<vector>: Template nested use compile error

[66maer]

Compiling the following scene with Visual Studio 2022, I get a compile error

I used C++17 inline static member variables

file: hello.hpp

#pragma once

#include <vector>
#include <deque>

template <typename T>
class MyQue {
    std::deque<T> que_;
};

class A{
    inline static MyQue<A> myque_;
};

file hello.cpp

#include "hello.h"

int main() {
    A a;
}

I found this weird problem with the following scenario

1. compile directly (Everything is the default configuration Debug/x64/C++17)
2. At this time, an error will be reported, an undefined type is used 'A'
3. Change deque to vector, compile through std::deque<T> que_; ----->std::vector<T> que_;

I don't understand, why deque doesn't work properly

// in an experiment，If you do not clear the cache at this time and change back to deque, the compilation can still pass.

These codes can be compiled smoothly in linux gcc-9

[fsb4000]

Partially reduced example:

#include <deque>
using namespace std;
template <class _Ty, class _Alloc = allocator<_Ty>>
class deque {
private:
    using _Alty = _Rebind_alloc_t<_Alloc, _Ty>;
    using _Alty_traits = allocator_traits<_Alty>;
    using _Alpty = _Rebind_alloc_t<_Alloc, typename _Alty_traits::pointer>;
    using _Alpty_traits = allocator_traits<_Alpty>;
    using _Mapptr = typename _Alpty_traits::pointer;

    using _Scary_val = _Deque_val<conditional_t<_Is_simple_alloc_v<_Alty>, _Deque_simple_types<_Ty>,
        _Deque_iter_types<_Ty, typename _Alty_traits::size_type, typename _Alty_traits::difference_type,
        typename _Alty_traits::pointer, typename _Alty_traits::const_pointer, _Ty&, const _Ty&, _Mapptr>>>;
    static constexpr int _Block_size = _Scary_val::_Block_size;

public:
    deque() = default;
};

template <typename T>
class MyQue {
    ::deque<T> que_;
};

class A {
    inline static MyQue<A> myque_;
};

int main() {
    A a;
    (void)a;
}

clang-cl /nologo /std:c++17 /EHsc /W4 /WX main.cpp
# works

clang-cl -v
clang version 14.0.5
Target: x86_64-pc-windows-msvc
Thread model: posix
InstalledDir: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\Llvm\x64\bin

cl /nologo /std:c++17 /EHsc /W4 /WX main.cpp

C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.33.31627\include\deque(558): error C2027: use of undefined type 'A'
main.cpp(26): note: see declaration of 'A'
main.cpp(15): note: see reference to class template instantiation 'std::_Deque_val<std::_Deque_simple_types<_Ty>>' being compiled
        with
        [
            _Ty=A
        ]
main.cpp(23): note: see reference to class template instantiation 'deque<T,std::allocator<_Ty>>' being compiled
        with
        [
            T=A,
            _Ty=A
        ]
main.cpp(27): note: see reference to class template instantiation 'MyQue<A>' being compiled

[fsb4000]

Oh, I remembered. This is known and it will be "won't fix".
Sorry.
More info: #2506 and #108

[66maer]

自动回复：我已经收到您的邮件，谢谢。

[CaseyCarter]

@fsb400 nailed it, this is a duplicate of #2506. (A is not complete when declaring its static member myque_.)

[66maer]

自动回复：我已经收到您的邮件，谢谢。