syntax_data: {"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let ClosureExpr { closure_id, args, upvars, movability, fake_reads } = expr;
context_before:     fn print_closure_expr(&mut self, expr: &ClosureExpr<'tcx>, depth_lvl: usize) {