void delegate() → void delegate() shared

@safe shared(void delegate()) f(void delegate() d)
{
    return d;
}

@safe void delegate() shared g(shared(void delegate()) d)
{
    return delegate() shared { d(); };
}

@safe void delegate() shared very_bad(void delegate() d)
{
    return g(f(d));
}

void main()
{
}