syntax_data: {"ast_node_type":"variable","tokens":[{"end":47,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let xs = self.runs.iter().copied();
context_before:             let mut runs: SmallVec<[(Byte, S); 1]> = SmallVec::new();
context_after:             let ys = other.runs.iter().copied();