syntax_data: {"ast_node_type":"variable","tokens":[{"end":82,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let mut checker = PackedRefChecker { body, tcx, typing_env, source_info };
context_before:         let source_info = SourceInfo::outermost(body.span);
context_after:         checker.visit_body(body);