Beedle - Oracle free perpetual lending

Summary

State variables only set in the constructor should be declared immutable

Vulnerability Details

Use immutable if you want to assign a permanent value at construction. Use constant if you already know the permanent value. Both get directly embedded in bytecode, saving SLOAD.
Variables only set in the constructor and never edited afterwards should be marked as immutable, as it would avoid the expensive storage-writing operation in the constructor (around 20_000 gas) and replace the expensive storage-reading operations (first time 2_100 gas, every other time 100 gas) to a less expensive value reading (3 gas)

https://github.com/Cyfrin/2023-07-beedle/blob/main/src/Lender.sol#L67

https://github.com/Cyfrin/2023-07-beedle/blob/main/src/utils/Ownable.sol#L8

Impact

Gas savings

Tools Used

Manual review

Recommendations

Set these variables as immutable