syntax_data: {"ast_node_type":"function","tokens":[{"end":49,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn visit_arm(&mut self, arm: &'p Arm<'tcx>) {
context_before:     #[instrument(level = "trace", skip(self))]
context_after:         self.with_lint_level(arm.lint_level, |this| {