如何修复 Solidity 上的 Stack Too Deep 错误？

Question

On solidity, I keep getting the 'stack too deep' error. I was wondering if anyone can help me fix this with in following code:

function _getTValues(uint256 tAmount) private view returns (uint256, uint256, uint256, uint256, uint256, uint256) {
        uint256 tFee = calculateTaxFee(tAmount);
        uint256 tLiquidity = calculateLiquidityFee(tAmount);
        uint256 tDev = calculateDevFee(tAmount);
        uint256 tBurn = calculateBurnFee(tAmount);
        uint256 tCharity = calculateCharityFee(tAmount);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tLiquidity);
                tTransferAmount = tTransferAmount.sub(tDev);
                tTransferAmount = tTransferAmount.sub(tCharity);
                tTransferAmount = tTransferAmount.sub(tBurn);

        return (tTransferAmount, tFee, tLiquidity, tDev, tBurn, tCharity);
    }

Thanks!

Answer 1

You cannot have more than 16 local variable (iirc) but in this particular case you don't really need them all. Safemoon has a lot of redundant code, especially in the getValues and transfer functions. I suggest you have a look at the way this is done in SafeToken - https://github.com/solidity-guru/safetoken/blob/main/safetoken.sol

The only reason _getTValues is calculating all those t values is to subtract them from the tTransferAmount ... but you could just use the sum of all fees, eg

function _getTValues(uint256 tAmount) ... {
    uint256 tFeesSum = calculateSumOfFees(tAmount);
    uint256 tTransferAmount = tAmount - tFeesSum; // no need to use SafeMath in solidity ^0.8
    return tTransferAmount;
}