Gas Optimizations

[code423n4]

GAS

G-01: for loop gas optimization

ForgottenRunesWarriorsMinter.sol#L162
ForgottenRunesWarriorsMinter.sol#L220
ForgottenRunesWarriorsMinter.sol#L259
ForgottenRunesWarriorsMinter.sol#L355

Unnecessary to update uint to default value of zero.
Prefix instead of postfix increments and unchecked increments can save gas.

Taking all changes into account I recommend change a loop like this:

for (uint256 i = 0; i < numWarriors; i++) {
    _mint(msg.sender);
}

To this:

for (uint256 i; i < numWarriors;) {
    _mint(msg.sender);
    unchecked { ++i; }
}

G-02: Parameters order could save gas on mint fail

ForgottenRunesWarriorsMinter.sol#L163

Parameters daMinters, daAmountPaid, daNumMinted and numSold are not necessary to _mint. Therefore gas could be saved in case _mint reverts if _mint was set before such parameters. Check example below.

for (uint256 i = 0; i < numWarriors; i++) {
    _mint(msg.sender);
}

daMinters.push(msg.sender);
daAmountPaid[msg.sender] += msg.value;
daNumMinted[msg.sender] += numWarriors;
numSold += numWarriors;

if (numSold == maxDaSupply) {
    // optimistic: save gas by not setting on every mint, but will
    // require manual `setFinalPrice` before refunds if da falls short
    finalPrice = currentPrice;
}

G-03: No need to use _msgSender

ForgottenRunesWarriorsGuild.sol#L101

The use of _msgSender when there is no implementation of a meta transaction mechanism that uses it, such as EIP-2771, very slightly increases gas consumption.

I suggest replacing _msgSender with msg.sender if there is no mechanism to support meta-transactions like EIP-2771 implemented.

G-04: Gas can be saved by shortening syntax

ForgottenRunesWarriorsMinter.sol#L182

Gas could be saved by changing:

require(mintlistMinted[msg.sender] == false, 'Already minted');

To:

require(!mintlistMinted[msg.sender], 'Already minted');

G-05: Lore R contains very large string

ForgottenRunesWarriorsGuild.sol#L33

Having in mind that this might be unnegotiable I suggest shortening Lore R to less than 32 bytes to save gas.