Function rustc_mir_transform::check_unsafety::is_enclosed

fn is_enclosed(
    tcx: TyCtxt<'_>, 
    used_unsafe: &FxHashSet<HirId>, 
    id: HirId, 
    unsafe_op_in_unsafe_fn_allowed: bool
) -> Option<(&'static str, HirId)>

Returns the HirId for an enclosing scope that is also unsafe.