syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // takes `&self`, but it needs to modify the analysis. This is also the
context_before:     // The `RefCell` is used because `<Formatter as Labeller>::node_label`
context_after:     // reason for the `Formatter`/`BlockFormatter` split; `BlockFormatter` has