let mark_to_prop_to_caller_input call_opt pdg_caller sel_elem m =
match m with
| true, M.Glob -> Some m
| true, M.Loc ->
call_in_to_check :=
(pdg_caller, call_opt, sel_elem, m) :: !call_in_to_check;
None
| _ -> fatal "cannot propagate invisible mark@."