Prevent users from sending Bread tokens to the token contract address (address(this))

[RonTuretzky]

Problem

Currently, users can mistakenly send Bread tokensdirectly to the Bread token contract address using , which results in the tokens being lost or locked. This is a common issue in ERC20 contracts where users may not realize that sending tokens to the contract address is unsafe.

Requirements

• Prevent users from sending Bread tokens or ETH to the Bread token contract address (i.e., using address(this)).
• Add logic to revert or prevent such transactions.
• Provide user feedback (via revert messages) if a transfer is attempted to the token contract address.
• Update relevant documentation and tests.

Proposed Solution

• Implement a check in the transfer and transferFrom functions to revert if the recipient address is address(this).
• Implement a receive() and/or fallback() function that reverts to prevent accidental ETH transfers.

Sequence Diagram

sequenceDiagram
    participant User
    participant BreadTokenContract
    User->>BreadTokenContract: transfer(address(this), amount)
    BreadTokenContract-->>User: revert("Cannot send to token contract address")

    User->>BreadTokenContract: send ETH to address(this)
    BreadTokenContract-->>User: revert("Cannot send ETH to token contract address")

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Solidity Code Snippet

// Example for ERC20 transfer and transferFrom prevention
function transfer(address to, uint256 amount) public override returns (bool) {
    require(to != address(this), "Cannot send to token contract address");
    return super.transfer(to, amount);
}

function transferFrom(address from, address to, uint256 amount) public override returns (bool) {
    require(to != address(this), "Cannot send to token contract address");
    return super.transferFrom(from, to, amount);
}

Acceptance Criteria

• Attempting to transfer tokens to the contract address should revert with a clear error message.
• Documentation and tests are updated to reflect this behavior.