syntax_data: {"ast_node_type":"variable","tokens":[{"end":41,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let index = self.lo_or_index;
context_before:             // Fully-interned or partially-interned format.
context_after:             let data = with_span_interner(|interner| interner.spans[index as usize]);