EMC Finance & Bridge

The `Bridge._chainID` is set in the constructor and can be arbitrary. It is not used by the contract. According to the parameter description: ```sol=113 @param chainID ID of chain the Bridge contract exists on. ``` The `chainID` should represent the ID of the chain on which the contract is deployed. To ensure accuracy, it is recommended to use: ```sol uint256 chainId; assembly { chainId := chainid() } ```

The specific role is assigned with `DEFAULT_ADMIN_ROLE` as the role admin. However, the assignment here is redundant, as `DEFAULT_ADMIN_ROLE` will be the role admin for any role by default.

The `approve()` and `transferFrom()` functions are vulnerable to front-run attacks. This is because the `approve()` method overwrites the current allowance without checking if the spender has already used it. Consequently, if the spender has already spent the amount, the `approve` function will still approve a new amount.

The smart contract contains assembly code blocks, which enable direct interaction with the Ethereum Virtual Machine (EVM) and permits developers to write low-level code that manipulates the EVM. This low-level access is error-prone and can introduce complexity, vulnerabilities, and logic errors. ```sol=102 assembly { amount := calldataload(0xC4) recipientAddress := mload(0x40) lenRecipientAddress := calldataload(0xE4) mstore(0x40, add(0x20, add(recipientAddress, lenRecipientAddress))) calldatacopy( recipientAddress, // copy to destinationRecipientAddress 0xE4, // copy from calldata @ 0x104 sub(calldatasize(), 0xE) // copy size (calldatasize - 0x104) ) } ``` The code contains bugs: 0xE used instead of 0xE4. Offsets in GenericHandler are wrong. Some comments are misleading and contradict the code.

The use of function `_setupRole()` from inherited contract `AccessControlEnumerable` is deprecated in favor of directly calling internal function `_grantRole()`. Since function `_setupRole()` only calls function `_grantRole()`, it is more direct to use the latter function instead.

There should always be events emitted in the sensitive functions that are controlled by centralization roles.

```sol=469 require(proposal._status != ProposalStatus.Cancelled, "Proposal already cancelled"); ``` If expired, the proposal can be cancelled by the admin or relayer even if it was already executed. The status will be changed to Cancelled and the misleading event emitted.

In the `WEMC` token implementation the lack of validation on the `to` parameter in the `transfer()` and `transferFrom()` functions allows tokens to be sent to the zero address. This may result in lost tokens or unexpected behavior.

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.