syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //!   visitor might provide custom handling only for some types of interest, or
context_before: //! - A `TypeVisitor` may also call into a `TypeSuperVisitable` impl, because each
context_after: //!   only for some variants of each type of interest, and then use default