syntax_data: {"ast_node_type":"function","tokens":[{"end":55,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn visit_pat(&mut self, pat: &'a thir::Pat<'tcx>) {
context_before:     #[instrument(skip(self), level = "debug")]
context_after:         self.is_poly |= self.pat_is_poly(pat);