{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
                        let ret_sp = decl.output.span();
                    if let Some((fn_def_id, decl)) = self.get_fn_decl(blk.hir_id) {
                        if let Some(block_sp) = self.parent_item_span(blk.hir_id) {