syntax_data: {"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! - The `TypeFoldable` impls handle most of the traversal, and call into
context_before: //! custom fold operations that are specific to the folder.
context_after: //!   `TypeFolder`/`FallibleTypeFolder` when they encounter a type of interest.