syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// which means in practice almost every foldable type needs to also be
context_before: /// `TypeFolder` instances use the methods in `TypeVisitableExt` while folding,
context_after: /// visitable. (However, there are some types that are visitable without being