let find_call_input_nodes pdg_caller call_stmt in_key =
  match in_key with
  | PdgIndex.Signature.InCtrl
  | PdgIndex.Signature.InNum _ ->
    let idx = Pdg.get_index pdg_caller in
    let _, call_sgn = FctIndex.find_call idx call_stmt in
    let node = PdgIndex.Signature.find_in_info call_sgn in_key in
    [ node, None ], None
  | PdgIndex.Signature.InImpl zone ->
    find_location_nodes_at_stmt pdg_caller call_stmt ~before:true zone