{"ast_node_type":"other","tokens":[{"end":92,"kind":"keyword","start":0,"text":"MirLowerError::ImplementationError(\"current_loop_blocks"}]}
            MirLowerError::ImplementationError("current_loop_blocks is corrupt".to_owned()),
        let my = mem::replace(&mut self.current_loop_blocks, prev).ok_or(
        )?;