syntax_data: {"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! - A `TypeFolder`/`FallibleTypeFolder` may call into another `TypeFoldable`
context_before: //!   `TypeFolder`/`FallibleTypeFolder` when they encounter a type of interest.
context_after: //!   impl, because some of the types of interest are recursive and can contain