syntax_data: {"ast_node_type":"variable","tokens":[{"end":33,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let tcx = self.tcx();
context_before:             let cycle = stack.iter().skip(1).take_while(|s| s.depth >= cycle_depth);
context_after:             let cycle = cycle.map(|stack| stack.obligation.predicate.upcast(tcx));