syntax_data: {"ast_node_type":"function","tokens":[{"end":61,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn unstable_opts_incremental_ignore_spans(&self) -> bool;
context_before:     /// we don't have easy access to a `Session`
context_after:     fn def_span(&self, def_id: LocalDefId) -> Span;