In this paper, we propose a new diagnostic for movement. It has been argued in the computational linguistics literature that some constraints can be formalized by path constraints on the sequence of their c-commanders (Graf and Shafiei 2019), and that some constraints can be formalized by the tree configuration they appear in (Graf and Heinz 2015). It holds that path constraints are a special case of tree constraints. We make the observation that path constraints cannot account for phenomena that have been argued to involve movement of the element requiring licensing, namely for ATB-extraction and parasitic gaps. However, the reverse does not hold: adjuncts islands and freezing effects, which also involve movement, can be formalized by path constraints. We thus propose the following one-way generalization: Whenever a phenomenon cannot be captured by path constraints, and can be captured by tree constraints, this phenomenon involves movement. We contend that this is not surprising given the fact that constraints on the well-formedness of the Move operation cannot be captured by path constraints, and rather must be captured by tree constraints (Graf 2018).