syntax_data: {"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // Closure used in `RegionFolder` to create names for anonymous late-bound
context_before:             let trim_path = with_forced_trimmed_paths();
context_after:             // regions. We use two `DebruijnIndex`es (one for the currently folded