syntax_data: {"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let to = u64::try_from(suffix.len()).unwrap();
context_before:                 let from = u64::try_from(prefix.len()).unwrap();
context_after:                 for subpattern in prefix.iter() {