syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"//!"}]}
source_snippet: //! within the `SourceMap`, which upon request can be converted to line and column
context_before: //! [`Span`] and used pervasively in the compiler. They are absolute positions
context_after: //! information, source code snippets, etc.