syntax_data: {"ast_node_type":"import","tokens":[{"end":81,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //!   impl, because each folder might provide custom handling only for some types
context_before: //! - A `TypeFolder`/`FallibleTypeFolder` may also call into a `TypeSuperFoldable`
context_after: //!   of interest, or only for some variants of each type of interest, and then