Function register_field_slots 

fn register_field_slots<'tcx>(
    tcx: TyCtxt<'tcx>,
    ty: Ty<'tcx>,
    base_slot: &Slot,
    _base_idx: usize,
    graph: &mut PtsGraph,
    field_depth: usize,
    deref_depth: usize,
    ty_env: TypingEnv<'tcx>,
)