syntax_data: {"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let oldest = if lo_cache_idx != -1 || hi_cache_idx != -1 {
context_before:         // No cache hit or cache hit for only one of span lo and hi.
context_after:             let avoid_idx = if lo_cache_idx != -1 { lo_cache_idx } else { hi_cache_idx };