syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":".rposition(|scope|"}]}
source_snippet:             .rposition(|scope| scope.region_scope == region_scope)
context_before:             .iter()
context_after:             .unwrap_or_else(|| span_bug!(span, "region_scope {:?} does not enclose", region_scope))