{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"//"}]}
                // boring local was found, which we ignore like NLLs do to match its diagnostics.
                // Here, under NLL: no cause was found. Under polonius: no cause was found, or a
                if let Some(region) = self.to_error_region_vid(borrow_region_vid) {