first commit

.eslintignore

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+dist
+node_modules
+coverage

.eslintrc.js

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+/*
+👋 Hi! This file was autogenerated by tslint-to-eslint-config.
+https://github.com/typescript-eslint/tslint-to-eslint-config
+
+It represents the closest reasonable ESLint configuration to this
+project's original TSLint configuration.
+
+We recommend eventually switching this configuration to extend from
+the recommended rulesets in typescript-eslint.
+https://github.com/typescript-eslint/tslint-to-eslint-config/blob/master/docs/FAQs.md
+
+Happy linting! 💖
+*/
+module.exports = {
+    "env": {
+        "es6": true,
+        "node": true
+    },
+    "extends": [
+        "plugin:@typescript-eslint/recommended",
+        "plugin:@typescript-eslint/recommended-requiring-type-checking"
+    ],
+    "parser": "@typescript-eslint/parser",
+    "parserOptions": {
+        "project": "tsconfig.json",
+        "sourceType": "module"
+    },
+    "plugins": [
+        "@typescript-eslint"
+    ]
+};

.gitattributes

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+*.sol linguist-language=Solidity

.gitignore

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+# Temp & IDE files
+.vscode/
+*~
+*.swp
+*.swo
+
+# Buidler files
+cache
+artifacts
+node_modules/
+output/
+
+# Truffle files
+.infuraKey
+.secret
+build/
+
+# Solidity-coverage
+coverage/
+.coverage_contracts/
+coverage.json
+
+# Yarn
+yarn-error.log
+
+# NPM
+package-lock.json
+
+# Crytic
+crytic-export/

.prettierrc

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+{
+  "semi": false,
+  "singleQuote": true,
+  "printWidth": 120
+}

.solcover.js

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+module.exports = {
+    skipFiles: [
+    ]
+}

.solhint.json

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+{
+    "extends": "solhint:recommended",
+    "plugins": [],
+    "rules": {
+        "avoid-throw": "off",
+        "avoid-suicide": "error",
+        "avoid-sha3": "warn",
+        "compiler-version": "off",
+        "no-empty-blocks": "off"
+    }
+}

README.md

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+# ERC20 Flash
+
+This project is the reference implementation the the [ERC 3156 Flash Loan](https://github.com/ethereum/EIPs/pull/3156) standard.
+
+The contracts included inherit from OpenZeppelin's ERC20.
+
+## How to Use
+
+`ERC20FlashLoan` and `ERC20FlashMint` are `ERC20` contracts. You can just inherit from them and you are done from the smart contracts point of view.
+
+```
+contract MyContract is ERC20FlashMint {
+
+    constructor (string memory _name, string memory _symbol, uint256 _fee) public ERC20FlashMint(_name, _symbol, _fee) {...}
+
+    ...
+}
+```
+
+```
+contract MyContract is ERC20FlashLoan {
+
+    constructor (string memory _name, string memory _symbol, IERC20 _asset, uint256 _fee) public ERC20FlashLoan(_name, _symbol, _asset, _fee) {...}
+
+    ...
+}
+```
+
+The `_fee` parameter is a divisor to be applied on the flash loaned values. The `receiver` of the `flashLoan` will have to pay back `value + value/fee`.

buidler.config.ts

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+import { usePlugin } from "@nomiclabs/buidler/config";
+
+usePlugin("@nomiclabs/buidler-truffle5");
+usePlugin("solidity-coverage");
+usePlugin("buidler-gas-reporter");
+
+export default {
+    defaultNetwork: "buidlerevm",
+    solc: {
+        version: "0.7.5",
+        optimizer: {
+            enabled: true,
+            runs: 200
+        },
+    },
+    gasReporter: {
+        enabled: true
+    },
+    paths: {
+        artifacts: "./build",
+        coverage: "./coverage",
+        coverageJson: "./coverage.json",
+    },
+    networks: {
+        coverage: {
+            url: "http://127.0.0.1:8555",
+        },
+    },
+};

codechecks.yml

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+checks:
+  - name: eth-gas-reporter/codechecks

contracts/ERC20FlashLoan.sol

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+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.7.5;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/math/SafeMath.sol";
+
+
+interface flashBorrowerLike {
+    function onFlashLoan(address user, uint256 value, uint256 fee, bytes calldata) external;
+}
+
+/**
+ * @author Alberto Cuesta Cañada
+ * @dev Extension of {ERC20} that allows flash lending.
+ */
+contract ERC20FlashLoan is ERC20 {
+    using SafeMath for uint256;
+
+    IERC20 public immutable asset;
+    uint256 public fee;
+
+    constructor(string memory name, string memory symbol, IERC20 asset_, uint256 fee_) ERC20(name, symbol) {
+        asset = asset_;
+        fee = fee_;
+    }
+
+    /**
+     * @dev Loan `value` tokens to `receiver`, which needs to return them plus a 0.1% fee to this contract within the same transaction.
+     * @param receiver The contract receiving the tokens, needs to implement the `onFlashLoan(address user, uint256 value, uint256 fee, bytes calldata)` interface.
+     * @param value The amount of tokens lent.
+     * @param data A data parameter to be passed on to the `receiver` for any custom use.
+     */
+    function flashLoan(address receiver, uint256 value, bytes calldata data) external {
+        uint256 _fee = value.div(fee);
+        uint256 supplyTarget = totalSupply().add(_fee);
+        asset.transfer(receiver, value);
+        flashBorrowerLike(receiver).onFlashLoan(msg.sender, value, _fee, data);
+        require(totalSupply() >= supplyTarget);
+    }
+}

contracts/ERC20FlashMint.sol

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+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.7.5;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/math/SafeMath.sol";
+
+
+interface flashBorrowerLike {
+    function onFlashLoan(address user, uint256 value, uint256 fee, bytes calldata) external;
+}
+
+/**
+ * @author Alberto Cuesta Cañada
+ * @dev Extension of {ERC20} that allows flash minting.
+ */
+contract ERC20FlashMint is ERC20 {
+    using SafeMath for uint256;
+
+    uint256 public fee;
+
+    constructor (string memory name, string memory symbol, uint256 fee_) ERC20(name, symbol) {
+        fee = fee_;
+    }
+
+    /**
+     * @dev Loan `value` tokens to `receiver`, which needs to return them plus a 0.1% fee to this contract within the same transaction.
+     * @param receiver The contract receiving the tokens, needs to implement the `onFlashLoan(address user, uint256 value, uint256 fee, bytes calldata)` interface.
+     * @param value The amount of tokens lent.
+     * @param data A data parameter to be passed on to the `receiver` for any custom use.
+     */
+    function flashLoan(address receiver, uint256 value, bytes calldata data) external {
+        uint256 _fee = value.div(fee);
+        _mint(receiver, value);
+        flashBorrowerLike(receiver).onFlashLoan(msg.sender, value, _fee, data);
+        _burn(address(this), value.add(_fee));
+    }
+}

migrations/1_initial_migration.js

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+const Migrations = artifacts.require('Migrations');
+
+module.exports = (deployer) => {
+    deployer.deploy(Migrations);
+};

package.json

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+{
+  "name": "erc20flash",
+  "version": "0.0.1",
+  "description": "Solidity contracts implementing flash lending",
+  "author": "Alberto Cuesta Cañada",
+  "engines": {
+    "node": ">= 10.12.0",
+    "npm": ">= 6.4.0",
+    "yarn": ">= 1.10.0"
+  },
+  "files": [
+    "/contracts/ERC20FlashLoan.sol",
+    "/contracts/ERC20FlashMint.sol"
+  ],
+  "keywords": [
+    "solidity",
+    "ethereum",
+    "smart",
+    "contracts",
+    "security"
+  ],
+  "scripts": {
+    "build": "buidler compile",
+    "test": "buidler test test/*.ts",
+    "ganache": "./scripts/ganache.sh",
+    "deploy:ganache": "yarn ganache && truffle migrate",
+    "coverage": "buidler coverage --network coverage --temp build --testfiles 'test/*.ts'",
+    "lint:js": "prettier ./test/**/*.js --write",
+    "lint:sol": "solhint -f table contracts/**/*.sol"
+  },
+  "dependencies": {
+    "@openzeppelin/contracts": "3.3.0"
+  },
+  "devDependencies": {
+    "@nomiclabs/buidler": "^1.3.8",
+    "@nomiclabs/buidler-truffle5": "^1.3.4",
+    "@nomiclabs/buidler-web3": "^1.3.4",
+    "@openzeppelin/contracts": "3.3.0",
+    "@openzeppelin/test-helpers": "^0.5.6",
+    "@truffle/hdwallet-provider": "^1.0.40",
+    "@types/mocha": "^8.0.0",
+    "buidler-gas-reporter": "0.1.4-beta.4",
+    "chai": "4.2.0",
+    "ethereumjs-util": "^7.0.3",
+    "ethers": "^5.0.7",
+    "ganache-time-traveler": "^1.0.14",
+    "mocha": "^7.1.0",
+    "prettier": "^2.0.5",
+    "solhint": "^3.2.0",
+    "solidity-coverage": "^0.7.9",
+    "truffle": "^5.1.39",
+    "truffle-typings": "^1.0.8",
+    "ts-node": "^8.10.2",
+    "typescript": "^3.9.7"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/albertocuestacanada/ERC20Flash.git"
+  },
+  "license": "GPL-3.0-or-later",
+  "bugs": {
+    "url": "https://github.com/albertocuestacanada/ERC20Flash/issues"
+  },
+  "homepage": "https://github.com/albertocuestacanada/ERC20Flash"}

test/erc20flash.ts

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+const ERC20FlashLoan = artifacts.require('ERC20FlashLoan')
+const ERC20FlashMint = artifacts.require('ERC20FlashMint')
+
+// @ts-ignore
+import { expectRevert } from '@openzeppelin/test-helpers'
+
+type Contract = any
+
+contract('ERC20FlashMint', async (accounts: string[]) => {
+  let [owner, user] = accounts
+
+  let token: Contract
+  let name: string
+
+  beforeEach(async () => {
+    token = await ERC20FlashMint.new("Test", "TST", 1000, { from: owner })
+  })
+
+  it('tests to be added', async () => {
+  })
+})