syntax_data: {"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //!   `TypeVisitor` when they encounter a type of interest.
context_before: //! - The `TypeVisitable` impls handle most of the traversal, and call into
context_after: //! - A `TypeVisitor` may call into another `TypeVisitable` impl, because some of