Optix

In the contract `OptionERC721`, in the function `create()`, the amount locked may not be the same as the amount transferred. The calculated `remain` amount is transferred while the amount locked is `option.lockedAmount`. The result could be a mismatch of locked funds.

The **require** can be used to check for conditions and throw an exception if the condition is not met. It is better to provide a string message containing details about the error that will be passed back to the caller.

The requirement case is set to the value `true`. Therefore, the requirement will never fail.

```solidity=71 event SetGlobalAddressPair(address indexed byAccount, SetVariableType indexed eventType, address a1, address a2, bool from, bool to); ``` - `SetGlobalAddressPair` is declared in `IStructs` but never emitted. --- ```solidity=72 event SetGlobalAddressPairBoolState(address indexed byAccount, SetVariableType indexed eventType, address a1, address a2, BoolState from, BoolState to); ``` - `SetGlobalAddressPairBoolState` is declared in `IStructs` but never emitted.

The linked parameters are never used.

The role `CONTRACT_CALLER_ROLE` is defined in the `OptionsVaultFactory` contract but it is never used.

In the contract `SimpleSeller`, in the function `findMatchFee()`, the variable `matchStrike` is instantiated locally and assigned but never utilized.

The linked variables assigned in the constructor can be declared as `immutable`. Immutable state variables can be assigned during contract creation but will remain constant throughout the lifetime of a deployed contract. A big advantage of immutable variables is that reading them is significantly cheaper than reading from regular state variables since they will not be stored in storage.