Function once_cell::sync::_dummy

fn _dummy()

struct S(*mut ());
unsafe impl Sync for S {}

fn share<T: Sync>(_: &T) {}
share(&once_cell::sync::OnceCell::<S>::new());

struct S(*mut ());
unsafe impl Sync for S {}

fn share<T: Sync>(_: &T) {}
share(&once_cell::sync::Lazy::<S>::new(|| unimplemented!()));