Inheriting from template instanciated with incomplete type

I have a struct template like the following:

// S.h
#pragma once

#include <vector>

template <typename T>
struct S
{
    std::vector<T*> ts;

    virtual ~S() { for (auto* t : ts) t->foo(); } 
    void attach(T& t) { this->ts.push_back(&t); }
};

Then, I inherit a non-template struct, ConcreteS, from S<A>; struct A being incomplete at this point, as I only forward declare it in ConcreteS.h:

// ConcreteS.h
#pragma once

#include "S.h"

struct A;
struct ConcreteS : public S<A>
// struct A incomplete here ^
{
    ConcreteS(); 
    ~ConcreteS() override; 
};

I include A.h in ConcreteS.cpp to make the definition of struct A visible to the implementation of ConcreteS's destructor:

// ConcreteS.cpp
#include "ConcreteS.h"
#include "A.h"

#include <cstdio>

ConcreteS::ConcreteS() { std::puts("ConcreteS()"); }
ConcreteS::~ConcreteS() { std::puts("~ConcreteS()"); }

Finally, I instanciate ConcreteS in function main:

// main.cpp
#include "ConcreteS.h"

int main()
{
    ConcreteS concreteS{};
}

The above code compiles (and runs) fine with:

• GCC 11.3.0;
• Clang 14.0.0.

The output is:

ConcreteS()
~ConcreteS()

But fails to compile on:

• Visual Studio 2019 (compiler: MSVC 19.29.30133.0);
• Visual Studio 2013 (compiler: MSVC 18.0.40629.0).

Here you are the error message from VS13 (the one from VS19 is similar):

Microsoft (R) Build Engine version 12.0.40629.0
[Microsoft .NET Framework, version 4.0.30319.42000]
Copyright (C) Microsoft Corporation. All rights reserved.

  Checking Build System
  Building Custom Rule <proj_path>/CMakeLists.txt
cl : Command line warning D9002: ignoring unknown option '/permissive-' [<proj_path>\build_vs13\tmp.vcxproj]
  A.cpp
  ConcreteS.cpp
  main.cpp
<proj_path>\S.h(10): error C2027: use of undefined type 'A' [<proj_path>\build_vs13\tmp.vcxproj]
          <proj_path>\ConcreteS.h(5) : see declaration of 'A'
          <proj_path>\S.h(10) : while compiling class template member function 'S<A>::~S(void)'
          <proj_path>\ConcreteS.h(8) : see reference to class template instantiation 'S<A>' being compiled
<proj_path>\S.h(10): error C2227: left of '->foo' must point to class/struct/union/generic type [<proj_path>\build_vs13\tmp.vcxproj]
  Generating Code...

Question: Who is right? Visual Studio or GCC/Clang?

For reference, I also post the declaration and definition of struct A and my CMakeLists.txt:

// A.h
#pragma once

struct A
{
    void foo() const;
};

// A.cpp
#include "A.h"
#include <cstdio>

void A::foo() const { std::puts("A::foo()"); }

# CMakeLists.txt
cmake_minimum_required(VERSION 3.6)
project(tmp)

add_executable(tmp A.cpp A.h ConcreteS.cpp ConcreteS.h S.h main.cpp)

if (MSVC)
    target_compile_options(tmp PRIVATE /W4 /WX /permissive-)
else()
    target_compile_options(tmp PRIVATE -Wall -Wextra -pedantic -Werror)
endif()