// REQUIRED_ARGS: -de -unittest
deprecated struct OldS21830 { }
struct NewS21830 { }
static if (1)
{
    auto test21830(T)(T t)
    if (is(T == NewS21830))
    {
        return T.init;
    }
}
deprecated auto test21830(T)(T t)
if (is(T == OldS21830))
{
    return T.init;
}
unittest
{
    auto b = test21830(NewS21830()); // error here about using test21830!OldS21830
}