syntax_data: {"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let ExternOpt { crate_name: name, path, options } =
context_before:     for arg in matches.opt_strs("extern") {
context_after:             split_extern_opt(early_dcx, unstable_opts, &arg).unwrap_or_else(|e| e.emit());