Function is_raw_ptr_wrapper 

pub fn is_raw_ptr_wrapper<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool

Whether def_id is a single-field struct wrapping a raw pointer (i.e. NonNull-shaped). Used by alias/ownership reasoning to recognize pointer wrappers — including local re-implementations — by their structure rather than by a std DefId.