Use Custom Error instead of Revert / Require String to Save Gas
Custom error from solidity 0.8.4 are cheaper than revert strings, custom error are defined using the error statement can use inside and outside the contract.
Consider making some constants as non-public to save gas
Reducing from public to private or internal can save gas when a constant isn’t used outside of its contract. I suggest changing the visibility from public to internal or private.
useage of uint / int smaller than 32 bytes incurs overhead
When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.
++i costs less gas compared to i++ or i += 1 for unsigned integer, as pre-increment is cheaper (about 5 gas per iteration). This statement is true even with the optimizer enabled.
i++ increments i and returns the initial value of i
I suggest using ++i instead of i++ to increment the value of an uint variable.
Same thing for --i and i--
The code should be refactored such that they no longer exist, or the block should do something useful,
such as emitting an event or reverting. If the contract is meant to be extended,
the contract should be abstract and the function signatures be added without any default implementation.
If the block is an empty if-statement block to avoid doing subsequent checks in the else-if/else conditions,
the else-if/else conditions should be nested under the negation of the if-statement,
because they involve different classes of checks, which may lead to the introduction of errors when the code is
later modified (if(x){}else if(y){...}else{...} => if(!x){if(y){...}else{...}})
Custom error from solidity 0.8.4 are cheaper than revert strings, custom error are defined using the
errorstatement can use inside and outside the contract.source https://blog.soliditylang.org/2021/04/21/custom-errors/
i suggest replacing revert / require error strings with custom error.
POC :
https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L267 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L285 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L297 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/utils/MerkleBase.sol#L62 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/utils/MerkleBase.sol#L78
Reducing from
publictoprivateorinternalcan save gas when a constant isn’t used outside of its contract. I suggest changing the visibility frompublictointernalorprivate.POC :
https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L15 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L17 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/modules/Buyout.sol#L37
When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.
resource : https://docs.soliditylang.org/en/v0.8.11/internals/layout_in_storage.html
Use a larger size then downcast where needed
POC :
https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L104 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L150 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/utils/SelfPermit.sol#L23 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/utils/SelfPermit.sol#L50
++icosts less gas compared toi++ori += 1++icosts less gas compared toi++ori += 1for unsigned integer, as pre-increment is cheaper (about 5 gas per iteration). This statement is true even with the optimizer enabled.i++incrementsiand returns the initial value ofiI suggest using
++iinstead ofi++to increment the value of an uint variable. Same thing for--iandi--POC:
https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L339 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/FERC1155.sol#L363
The code should be refactored such that they no longer exist, or the block should do something useful, such as emitting an event or reverting. If the contract is meant to be extended, the contract should be
abstractand the function signatures be added without any default implementation. If the block is an empty if-statement block to avoid doing subsequent checks in the else-if/else conditions, the else-if/else conditions should be nested under the negation of the if-statement, because they involve different classes of checks, which may lead to the introduction of errors when the code is later modified (if(x){}else if(y){...}else{...}=>if(!x){if(y){...}else{...}})POV :
https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/Vault.sol#L32 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/modules/Buyout.sol#L53 https://github.com/code-423n4/2022-07-fractional/blob/e2c5a962a94106f9495eb96769d7f60f7d5b14c9/src/modules/Migration.sol