syntax_data: {"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let mut obligations = PredicateObligations::with_capacity(predicates.len());
context_before:         let predicates = predicates.instantiate_own(tcx, args);
context_after:         for (index, (predicate, span)) in predicates.into_iter().enumerate() {