syntax_data: {"ast_node_type":"function","tokens":[{"end":71,"kind":"keyword","start":0,"text":"($($(#[$a:meta])*"}]}
source_snippet:     ($($(#[$a:meta])* fn $name:ident($helper:ident, $tl:ident);)+) => {
context_before: macro_rules! define_helper {
context_after:         $(