why the (*joinError) panic? i even can’t create a nil *joinError.

go 1.23.4

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xfb44180]

goroutine 5505 [running]:
errors.(*joinError).Unwrap(0x116c8aa0?)
    errors/join.go:61
errors.as({0x10d749e0?, 0x0?}, {0x10af6a20, 0xc002ca20a0}, {0x10af6a20?, 0xc002ca20a0?, 0xc0014794f0?}, {0x10d91190, 0x10bf7ca0})
    errors/wrap.go:132 +0x325
errors.As({0x10d749e0, 0x0}, {0x10af6a20, 0xc002ca20a0})
    errors/wrap.go:113 +0x1c8
github.com/Asutorufa/yuhaiin/pkg/net/dialer.MergeDnsError({0x10d749e0, 0x0}, {0x10d736a0, 0xc00117c220})
    github.com/Asutorufa/yuhaiin/pkg/net/dialer/happyeyeballsv2.go:138 +0xa6
github.com/Asutorufa/yuhaiin/pkg/net/dialer.(*happyEyeball).lookupIP(0xc00105c000, {0x10d85fc0, 0xc0011b2000}, 0x1)
    github.com/Asutorufa/yuhaiin/pkg/net/dialer/happyeyeballsv2.go:117 +0x19a
created by github.com/Asutorufa/yuhaiin/pkg/net/dialer.(*HappyEyeballsv2Dialer[...]).DialHappyEyeballsv2 in goroutine 5503
    github.com/Asutorufa/yuhaiin/pkg/net/dialer/happyeyeballsv2.go:273 +0x372

the MergeDnsError is, I want remove same dns error.

func MergeDnsError(err1, err2 error) error {
    de1 := &net.DNSError{}

    if !errors.As(err1, &de1) {
        return errors.Join(err1, err2)
    }

    de2 := &net.DNSError{}
    if !errors.As(err2, &de2) {
        return errors.Join(err1, err2)
    }

    if de1.Err == de2.Err {
        return err1
    }

    return errors.Join(err1, err2)
}

I tried erros.Join(nil,nil), but not panic.