syntax_data: {"ast_node_type":"other","tokens":[{"end":127,"kind":"keyword","start":0,"text":"($opt_name:ident,"}]}
source_snippet:     ($opt_name:ident, $opt_expr:expr, $error_format:expr, $for_crate_hash:expr, $hasher:expr, [TRACKED_NO_CRATE_HASH]) => {{}};
context_before:     ($opt_name:ident, $opt_expr:expr, $error_format:expr, $for_crate_hash:expr, $hasher:expr, [TRACKED]) => {{}};
context_after:     ($opt_name:ident, $opt_expr:expr, $error_format:expr, $for_crate_hash:expr, $hasher:expr, [SUBSTRUCT]) => {