{"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"self.check_ptr_access_signed(b,"}]}
                self.check_ptr_access_signed(b, dist, CheckInAllocMsg::Dereferenceable)
                // origin pointer: `dist` is `a - b`, so it is based on `b`.
                    .map_err_kind(|_| {