syntax_data: {"ast_node_type":"variable","tokens":[{"end":55,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let outer_universe = self.infcx.universe();
context_before:         self.infcx.probe(|snapshot| -> Result<EvaluationResult, OverflowError> {
context_after:             let result = op(self)?;