Crash on 19.10, 20.0, and trunk

[AZero13]

https://godbolt.org/z/d5ha1EEj4

change the using WinAPIGLFunc = attribute((ms_abi)) GLFunc; to using WinAPIGLFunc = attribute((ms_abi)) Result (*)(Args...); and it doesnt crash

#include <stdint.h>
#include <utility>

template<class T>
class GLFunctor;

template<class Result, class... Args>
class GLFunctor<Result (Args...)>
{
	using GLFunc = Result (*)(Args...);

public:
	Result operator()(Args... args) const
	{
		using WinAPIGLFunc = __attribute__((ms_abi)) GLFunc;
		return reinterpret_cast<WinAPIGLFunc>(glProc)(std::forward<Args>(args)...);
	}
private:
	GLFunc glProc = nullptr;
};

GLFunctor<void (int pname)> test_functor;

void Test()
{
    test_functor(0);
}

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: AZero13 (AZero13)

https://godbolt.org/z/d5ha1EEj4

change the using WinAPIGLFunc = attribute((ms_abi)) GLFunc; to using WinAPIGLFunc = attribute((ms_abi)) Result (*)(Args...); and it doesnt crash

#include <stdint.h>
#include <utility>

template<class T>
class GLFunctor;

template<class Result, class... Args>
class GLFunctor<Result (Args...)>
{
	using GLFunc = Result (*)(Args...);

public:
	Result operator()(Args... args) const
	{
		using WinAPIGLFunc = __attribute__((ms_abi)) GLFunc;
		return reinterpret_cast<WinAPIGLFunc>(glProc)(std::forward<Args>(args)...);
	}
private:
	GLFunc glProc = nullptr;
};

GLFunctor<void (int pname)> test_functor;

void Test()
{
    test_functor(0);
}

[shafik]

Started in clang-19

[shafik]

@jcsxky git bisect points to d9d1ae6

[cor3ntin]

simplified a bit
https://godbolt.org/z/fxYh67dhM

template <class T> class GLFunctor;

template <class... Args> 
struct GLFunctor<void(Args...)> {
    using GLFunc = void (*)(Args...);
    void operator()(Args... args) const {
        using WinAPIGLFunc = __attribute__((ms_abi)) GLFunc;
    }
};

void Test() { GLFunctor<void(int pname)>{}(0); }