Gas Optimizations

[code423n4]

[G01]

Aproval is made to aura locker on each claim. It would be cheaper to do one max aproval in the constructor since aura locker is a trusted contract.

https://github.com/code-423n4/2022-05-aura/blob/4989a2077546a5394e3650bf3c224669a0f7e690/contracts/AuraMerkleDrop.sol#L132

[G02]

Variables that never change should be made immutable to save gas

https://github.com/code-423n4/2022-05-aura/blob/4989a2077546a5394e3650bf3c224669a0f7e690/contracts/AuraMerkleDrop.sol#L23

[G03]

reductionPerCliff variable is immutable but it can be changed to constant. It is setted in the constructor but it isn’t using inputs from the constructor, it is defined by 2 constants and it can be defined as constant.

https://github.com/code-423n4/2022-05-aura/blob/4989a2077546a5394e3650bf3c224669a0f7e690/contracts/Aura.sol#L52