syntax_data: {"ast_node_type":"function","tokens":[{"end":69,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn tys(&mut self, a: I::Ty, b: I::Ty) -> RelateResult<I, I::Ty> {
context_before:     #[instrument(skip(self), level = "trace")]
context_after:         if a == b {