ERC-20 Flash Mint

Extension of ERC-20 that provides flash loan support at the token level.

Usage

In order to make ERC-20 Flash Mint methods “external” so that other contracts can call them, you need to add the following code to your contract:

use openzeppelin_stylus::token::erc20::{
    self,
    extensions::{flash_mint, Erc20FlashMint, IErc3156FlashLender},
    Erc20,
};

#[derive(SolidityError, Debug)]
enum Error {
    Erc20(erc20::Error),
    Erc20FlashMint(flash_mint::Error),
}

#[entrypoint]
#[storage]
struct Erc20FlashMintExample {
    #[borrow]
    erc20: Erc20,
    #[borrow]
    flash_mint: Erc20FlashMint,
}

#[public]
#[inherit(Erc20)]
impl Erc20FlashMintExample {
    fn max_flash_loan(&self, token: Address) -> U256 {
        self.flash_mint.max_flash_loan(token, &self.erc20)
    }

    fn flash_fee(&self, token: Address, value: U256) -> Result<U256, Error> {
        Ok(self.flash_mint.flash_fee(token, value)?)
    }

    fn flash_loan(
        &mut self,
        receiver: Address,
        token: Address,
        value: U256,
        data: Bytes,
    ) -> Result<bool, Error> {
        Ok(self.flash_mint.flash_loan(
            receiver,
            token,
            value,
            data,
            &mut self.erc20,
        )?)
    }
}

Additionally, if you wish to set a flash loan fee and/or a fee receiver, you need to ensure proper initialization during contract deployment. Make sure to include the following code in your Solidity Constructor:

contract Erc20FlashMintExample {
    // ...

    uint256 private _flashFeeAmount;
    address private _flashFeeReceiverAddress;

    constructor(address flashFeeReceiverAddress_, uint256 flashFeeAmount_) {
        // ...
        _flashFeeReceiverAddress = flashFeeReceiverAddress_;
        _flashFeeAmount = flashFeeAmount_;
        // ...
    }
}