{"ast_node_type":"variable","tokens":[{"end":100,"kind":"keyword","start":0,"text":"let"}]}
        let elem_ty = match expected.to_option(&mut self.table).as_ref().map(|t| t.kind(Interner)) {
    ) -> chalk_ir::Ty<Interner> {
            Some(TyKind::Array(st, _) | TyKind::Slice(st)) => st.clone(),