StackTooDeepScope.js

 function removeLiquidityETHWithPermit(
        address token,
        uint weight,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
) external virtual override returns (uint amountToken, uint amountETH) {
        uint value = approveMax ? uint(-1) : liquidity;
        IPool pool = buildETHPool(token, weight);

        pool.permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountToken, amountETH) = removeLiquidityETH(token, weight, liquidity, amountTokenMin, amountETHMin, to, deadline);
}

function buildETHPool(address token, uint weight) internal view returns(IPool pool) {
        pool = IPool(IPoolFactory(factory).getPool(PoolKey.build(token, WETH, weight)));
}