syntax_data: {"ast_node_type":"variable","tokens":[{"end":52,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let edition = match matches.opt_str("edition") {
context_before: pub fn parse_crate_edition(early_dcx: &EarlyDiagCtxt, matches: &getopts::Matches) -> Edition {
context_after:         Some(arg) => Edition::from_str(&arg).unwrap_or_else(|_| {