Function analyze_path 

pub fn analyze_path(index: &SnapshotIndex<'_>, expression: &str) -> PathAnalysis

Walks a plain dotted path through the snapshots, segment by segment.

The walk crosses definitions: once a path leaves the resource’s own elements — Patient.name is a HumanName — it continues in the definition of that type. contentReference is followed the same way, which is what lets a recursive structure like Questionnaire.item.item resolve.