syntax_data: {"ast_node_type":"variable","tokens":[{"end":49,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                             let tcx = self.tcx();
context_before:                             let cycle = stack.iter().take_while(|s| s.depth > stack_term.1);
context_after:                             let cycle = cycle.map(|stack| stack.obligation.predicate.upcast(tcx));