Recon Coverage Report

Files 17 files

Files

Lines

2800

Coverage

79%

573 / 720

Actions

80% contracts/contracts/echidna/Debugger.sol

Lines covered: 4 / 5 (80%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

library Debugger {
    event Debug(string debugString);
    event Debug(string description, string data);
    event Debug(string prefix, string description, string data);
    event Debug(string description, bytes32 data);
    event Debug(string prefix, string description, bytes32 data);
    event Debug(string description, uint256 data);
    event Debug(string prefix, string description, uint256 data);
    event Debug(string description, int256 data);
    event Debug(string prefix, string description, int256 data);
    event Debug(string description, address data);
    event Debug(string prefix, string description, address data);
    event Debug(string description, bool data);
    event Debug(string prefix, string description, bool data);

    function log(string memory debugString) internal {
        emit Debug(debugString);
    }

    function log(string memory description, string memory data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        string memory data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, bytes32 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        bytes32 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, uint256 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        uint256 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, int256 data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        int256 data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, address data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        address data
    ) internal {
        emit Debug(prefix, description, data);
    }

    function log(string memory description, bool data) internal {
        emit Debug(description, data);
    }

    function log(
        string memory prefix,
        string memory description,
        bool data
    ) internal {
        emit Debug(prefix, description, data);
    }
}

95% contracts/contracts/echidna/EchidnaConfig.sol

Lines covered: 19 / 20 (95%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

/**
 * @title Top-level mixin for configuring the desired fuzzing setup
 * @author Rappie
 */
contract EchidnaConfig {
    address internal constant ADDRESS_VAULT = address(0x10000);
    address internal constant ADDRESS_OUTSIDER_USER = address(0x20000);

    address internal constant ADDRESS_USER0 = address(0x30000);
    address internal constant ADDRESS_USER1 = address(0x40000);

    // Will be set in EchidnaSetup constructor
    address internal ADDRESS_OUTSIDER_CONTRACT;
    address internal ADDRESS_CONTRACT0;
    address internal ADDRESS_CONTRACT1;

    // Toggle known issues
    //
    // This can be used to skip tests that are known to fail. This is useful
    // when debugging a specific issue, but should be disabled when running
    // the full test suite.
    //
    //   True => skip tests that are known to fail
    //   False => run all tests
    //
    bool internal constant TOGGLE_KNOWN_ISSUES = false;

    // Toggle known issues within limits
    //
    // Same as TOGGLE_KNOWN_ISSUES, but also skip tests that are known to fail
    // within limits set by the variables below.
    //
    bool internal constant TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS = false;

    // Starting balance
    //
    // Gives OUSD a non-zero starting supply, which can be useful to ignore
    // certain edge cases.
    //
    // The starting balance is given to outsider accounts that are not used as
    // accounts while fuzzing.
    //
    bool internal constant TOGGLE_STARTING_BALANCE = true;
    uint256 internal constant STARTING_BALANCE = 1_000_000e18;

    // Change supply
    //
    // Set a limit to the amount of change per rebase, which can be useful to
    // ignore certain edge cases.
    //
    //  True => limit the amount of change to a percentage of total supply
    //  False => no limit
    //
    bool internal constant TOGGLE_CHANGESUPPLY_LIMIT = true;
    uint256 internal constant CHANGESUPPLY_DIVISOR = 10; // 10% of total supply

    // Mint limit
    //
    // Set a limit the amount minted per mint, which can be useful to
    // ignore certain edge cases.
    //
    //  True => limit the amount of minted tokens
    //  False => no limit
    //
    bool internal constant TOGGLE_MINT_LIMIT = true;
    uint256 internal constant MINT_MODULO = 1_000_000_000_000e18;

    // Known rounding errors
    uint256 internal constant TRANSFER_ROUNDING_ERROR = 1e18 - 1;
    uint256 internal constant OPT_IN_ROUNDING_ERROR = 1e18 - 1;
    uint256 internal constant MINT_ROUNDING_ERROR = 1e18 - 1;

    /**
     * @notice Modifier to skip tests that are known to fail
     * @dev see TOGGLE_KNOWN_ISSUES for more information
     */
    modifier hasKnownIssue() {
        if (TOGGLE_KNOWN_ISSUES) return;
        _;
    }

    /**
     * @notice Modifier to skip tests that are known to fail within limits
     * @dev see TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS for more information
     */
    modifier hasKnownIssueWithinLimits() {
        if (TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS) return;
        _;
    }

    /**
     * @notice Translate an account ID to an address
     * @param accountId The ID of the account
     * @return account The address of the account
     */
    function getAccount(uint8 accountId)
        internal
        view
        returns (address account)
    {
        accountId = accountId / 64;
        if (accountId == 0) return account = ADDRESS_USER0;
        if (accountId == 1) return account = ADDRESS_USER1;
        if (accountId == 2) return account = ADDRESS_CONTRACT0;
        if (accountId == 3) return account = ADDRESS_CONTRACT1;
        require(false, "Unknown account ID");
    }
}

95% contracts/contracts/echidna/EchidnaHelper.sol

Lines covered: 70 / 73 (95%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaSetup.sol";
import "./Debugger.sol";

/**
 * @title Mixin containing helper functions
 * @author Rappie
 */
contract EchidnaHelper is EchidnaSetup {
    /**
     * @notice Mint tokens to an account
     * @param toAcc Account to mint to
     * @param amount Amount to mint
     * @return Amount minted (in case of capped mint with modulo)
     */
    function mint(uint8 toAcc, uint256 amount) public returns (uint256) {
        address to = getAccount(toAcc);

        if (TOGGLE_MINT_LIMIT) {
            amount = amount % MINT_MODULO;
        }

        hevm.prank(ADDRESS_VAULT);
        ousd.mint(to, amount);

        return amount;
    }

    /**
     * @notice Burn tokens from an account
     * @param fromAcc Account to burn from
     * @param amount Amount to burn
     */
    function burn(uint8 fromAcc, uint256 amount) public {
        address from = getAccount(fromAcc);
        hevm.prank(ADDRESS_VAULT);
        ousd.burn(from, amount);
    }

    /**
     * @notice Change the total supply of OUSD (rebase)
     * @param amount New total supply
     */
    function changeSupply(uint256 amount) public {
        if (TOGGLE_CHANGESUPPLY_LIMIT) {
            amount =
                ousd.totalSupply() +
                (amount % (ousd.totalSupply() / CHANGESUPPLY_DIVISOR));
        }

        hevm.prank(ADDRESS_VAULT);
        ousd.changeSupply(amount);
    }

    /**
     * @notice Transfer tokens between accounts
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function transfer(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);
        hevm.prank(from);
        // slither-disable-next-line unchecked-transfer
        ousd.transfer(to, amount);
    }

    /**
     * @notice Transfer approved tokens between accounts
     * @param authorizedAcc Account that is authorized to transfer
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function transferFrom(
        uint8 authorizedAcc,
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address authorized = getAccount(authorizedAcc);
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);
        hevm.prank(authorized);
        // slither-disable-next-line unchecked-transfer
        ousd.transferFrom(from, to, amount);
    }

    /**
     * @notice Opt in to rebasing
     * @param targetAcc Account to opt in
     */
    function optIn(uint8 targetAcc) public {
        address target = getAccount(targetAcc);
        hevm.prank(target);
        ousd.rebaseOptIn();
    }

    /**
     * @notice Opt out of rebasing
     * @param targetAcc Account to opt out
     */
    function optOut(uint8 targetAcc) public {
        address target = getAccount(targetAcc);
        hevm.prank(target);
        ousd.rebaseOptOut();
    }

    /**
     * @notice Approve an account to spend OUSD
     * @param ownerAcc Account that owns the OUSD
     * @param spenderAcc Account that is approved to spend the OUSD
     * @param amount Amount to approve
     */
    function approve(
        uint8 ownerAcc,
        uint8 spenderAcc,
        uint256 amount
    ) public {
        address owner = getAccount(ownerAcc);
        address spender = getAccount(spenderAcc);
        hevm.prank(owner);
        // slither-disable-next-line unused-return
        ousd.approve(spender, amount);
    }

    /**
     * @notice Get the sum of all OUSD balances
     * @return total Total balance
     */
    function getTotalBalance() public view returns (uint256 total) {
        total += ousd.balanceOf(ADDRESS_VAULT);
        total += ousd.balanceOf(ADDRESS_OUTSIDER_USER);
        total += ousd.balanceOf(ADDRESS_OUTSIDER_CONTRACT);
        total += ousd.balanceOf(ADDRESS_USER0);
        total += ousd.balanceOf(ADDRESS_USER1);
        total += ousd.balanceOf(ADDRESS_CONTRACT0);
        total += ousd.balanceOf(ADDRESS_CONTRACT1);
    }

    /**
     * @notice Get the sum of all non-rebasing OUSD balances
     * @return total Total balance
     */
    function getTotalNonRebasingBalance() public returns (uint256 total) {
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_VAULT)
            ? ousd.balanceOf(ADDRESS_VAULT)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_OUTSIDER_USER)
            ? ousd.balanceOf(ADDRESS_OUTSIDER_USER)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_OUTSIDER_CONTRACT)
            ? ousd.balanceOf(ADDRESS_OUTSIDER_CONTRACT)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_USER0)
            ? ousd.balanceOf(ADDRESS_USER0)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_USER1)
            ? ousd.balanceOf(ADDRESS_USER1)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_CONTRACT0)
            ? ousd.balanceOf(ADDRESS_CONTRACT0)
            : 0;
        total += ousd._isNonRebasingAccountEchidna(ADDRESS_CONTRACT1)
            ? ousd.balanceOf(ADDRESS_CONTRACT1)
            : 0;
    }
}

93% contracts/contracts/echidna/EchidnaSetup.sol

Lines covered: 15 / 16 (93%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./IHevm.sol";
import "./EchidnaConfig.sol";
import "./OUSDEchidna.sol";

contract Dummy {}

/**
 * @title Mixin for setup and deployment
 * @author Rappie
 */
contract EchidnaSetup is EchidnaConfig {
    IHevm hevm = IHevm(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
    OUSDEchidna ousd = new OUSDEchidna();

    /**
     * @notice Deploy the OUSD contract and set up initial state
     */
    constructor() {
        ousd.initialize(ADDRESS_VAULT, 1e18);

        // Deploy dummny contracts as users
        Dummy outsider = new Dummy();
        ADDRESS_OUTSIDER_CONTRACT = address(outsider);
        Dummy dummy0 = new Dummy();
        ADDRESS_CONTRACT0 = address(dummy0);
        Dummy dummy1 = new Dummy();
        ADDRESS_CONTRACT1 = address(dummy1);

        // Start out with a reasonable amount of OUSD
        if (TOGGLE_STARTING_BALANCE) {
            // Rebasing tokens
            hevm.prank(ADDRESS_VAULT);
            ousd.mint(ADDRESS_OUTSIDER_USER, STARTING_BALANCE / 2);

            // Non-rebasing tokens
            hevm.prank(ADDRESS_VAULT);
            ousd.mint(ADDRESS_OUTSIDER_CONTRACT, STARTING_BALANCE / 2);
        }
    }
}

92% contracts/contracts/echidna/EchidnaTestAccounting.sol

Lines covered: 37 / 40 (92%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaDebug.sol";
import "./EchidnaTestSupply.sol";

/**
 * @title Mixin for testing accounting functions
 * @author Rappie
 */
contract EchidnaTestAccounting is EchidnaTestSupply {
    /**
     * @notice After opting in, balance should not increase. (Ok to lose rounding funds doing this)
     * @param targetAcc Account to opt in
     */
    function testOptInBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        optIn(targetAcc);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceAfter <= balanceBefore);
    }

    /**
     * @notice After opting out, balance should remain the same
     * @param targetAcc Account to opt out
     */
    function testOptOutBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        optOut(targetAcc);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceAfter == balanceBefore);
    }

    /**
     * @notice Account balance should remain the same after opting in minus rounding error
     * @param targetAcc Account to opt in
     */
    function testOptInBalanceRounding(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        optIn(targetAcc);
        uint256 balanceAfter = ousd.balanceOf(target);

        int256 delta = int256(balanceAfter) - int256(balanceBefore);
        Debugger.log("delta", delta);

        // slither-disable-next-line tautology
        assert(-1 * delta >= 0);
        assert(-1 * delta <= int256(OPT_IN_ROUNDING_ERROR));
    }

    /**
     * @notice After opting in, total supply should remain the same
     * @param targetAcc Account to opt in
     */
    function testOptInTotalSupply(uint8 targetAcc) public {
        uint256 totalSupplyBefore = ousd.totalSupply();
        optIn(targetAcc);
        uint256 totalSupplyAfter = ousd.totalSupply();

        assert(totalSupplyAfter == totalSupplyBefore);
    }

    /**
     * @notice After opting out, total supply should remain the same
     * @param targetAcc Account to opt out
     */
    function testOptOutTotalSupply(uint8 targetAcc) public {
        uint256 totalSupplyBefore = ousd.totalSupply();
        optOut(targetAcc);
        uint256 totalSupplyAfter = ousd.totalSupply();

        assert(totalSupplyAfter == totalSupplyBefore);
    }

    /**
     * @notice Account balance should remain the same when a smart contract auto converts
     * @param targetAcc Account to auto convert
     */
    function testAutoConvertBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        // slither-disable-next-line unused-return
        ousd._isNonRebasingAccountEchidna(target);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceAfter == balanceBefore);
    }

    /**
     * @notice The `balanceOf` function should never revert
     * @param targetAcc Account to check balance of
     */
    function testBalanceOfShouldNotRevert(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        // slither-disable-next-line unused-return
        try ousd.balanceOf(target) {
            assert(true);
        } catch {
            assert(false);
        }
    }
}

96% contracts/contracts/echidna/EchidnaTestApproval.sol

Lines covered: 30 / 31 (96%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaTestMintBurn.sol";
import "./Debugger.sol";

/**
 * @title Mixin for testing approval related functions
 * @author Rappie
 */
contract EchidnaTestApproval is EchidnaTestMintBurn {
    /**
     * @notice Performing `transferFrom` with an amount inside the allowance should not revert
     * @param authorizedAcc The account that is authorized to transfer
     * @param fromAcc The account that is transferring
     * @param toAcc The account that is receiving
     * @param amount The amount to transfer
     */
    function testTransferFromShouldNotRevert(
        uint8 authorizedAcc,
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address authorized = getAccount(authorizedAcc);
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(amount <= ousd.balanceOf(from));
        require(amount <= ousd.allowance(from, authorized));

        hevm.prank(authorized);
        // slither-disable-next-line unchecked-transfer
        try ousd.transferFrom(from, to, amount) {
            // pass
        } catch {
            assert(false);
        }
    }

    /**
     * @notice Performing `transferFrom` with an amount outside the allowance should revert
     * @param authorizedAcc The account that is authorized to transfer
     * @param fromAcc The account that is transferring
     * @param toAcc The account that is receiving
     * @param amount The amount to transfer
     */
    function testTransferFromShouldRevert(
        uint8 authorizedAcc,
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address authorized = getAccount(authorizedAcc);
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(amount > 0);
        require(
            !(amount <= ousd.balanceOf(from) &&
                amount <= ousd.allowance(from, authorized))
        );

        hevm.prank(authorized);
        // slither-disable-next-line unchecked-transfer
        try ousd.transferFrom(from, to, amount) {
            assert(false);
        } catch {
            // pass
        }
    }

    /**
     * @notice Approving an amount should update the allowance and overwrite any previous allowance
     * @param ownerAcc The account that is approving
     * @param spenderAcc The account that is being approved
     * @param amount The amount to approve
     */
    function testApprove(
        uint8 ownerAcc,
        uint8 spenderAcc,
        uint256 amount
    ) public {
        address owner = getAccount(ownerAcc);
        address spender = getAccount(spenderAcc);

        approve(ownerAcc, spenderAcc, amount);
        uint256 allowanceAfter1 = ousd.allowance(owner, spender);

        assert(allowanceAfter1 == amount);

        approve(ownerAcc, spenderAcc, amount / 2);
        uint256 allowanceAfter2 = ousd.allowance(owner, spender);

        assert(allowanceAfter2 == amount / 2);
    }
}

95% contracts/contracts/echidna/EchidnaTestMintBurn.sol

Lines covered: 43 / 45 (95%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaDebug.sol";
import "./EchidnaTestAccounting.sol";

/**
 * @title Mixin for testing Mint and Burn functions
 * @author Rappie
 */
contract EchidnaTestMintBurn is EchidnaTestAccounting {
    /**
     * @notice Minting 0 tokens should not affect account balance
     * @param targetAcc Account to mint to
     */
    function testMintZeroBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        mint(targetAcc, 0);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceAfter == balanceBefore);
    }

    /**
     * @notice Burning 0 tokens should not affect account balance
     * @param targetAcc Account to burn from
     */
    function testBurnZeroBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        burn(targetAcc, 0);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceAfter == balanceBefore);
    }

    /**
     * @notice Minting tokens must increase the account balance by at least amount
     * @param targetAcc Account to mint to
     * @param amount Amount to mint
     * @custom:error testMintBalance(uint8,uint256): failed!💥
     *   Call sequence:
     *       changeSupply(1)
     *       testMintBalance(0,1)
     *   Event sequence:
     *       Debug(«balanceBefore», 0)
     *       Debug(«balanceAfter», 0)
     */
    function testMintBalance(uint8 targetAcc, uint256 amount)
        public
        hasKnownIssue
        hasKnownIssueWithinLimits
    {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        uint256 amountMinted = mint(targetAcc, amount);
        uint256 balanceAfter = ousd.balanceOf(target);

        Debugger.log("amountMinted", amountMinted);
        Debugger.log("balanceBefore", balanceBefore);
        Debugger.log("balanceAfter", balanceAfter);

        assert(balanceAfter >= balanceBefore + amountMinted);
    }

    /**
     * @notice Burning tokens must decrease the account balance by at least amount
     * @param targetAcc Account to burn from
     * @param amount Amount to burn
     * @custom:error testBurnBalance(uint8,uint256): failed!💥
     *   Call sequence:
     *       changeSupply(1)
     *       mint(0,3)
     *       testBurnBalance(0,1)
     *   Event sequence:
     *       Debug(«balanceBefore», 2)
     *       Debug(«balanceAfter», 2)
     */
    function testBurnBalance(uint8 targetAcc, uint256 amount)
        public
        hasKnownIssue
        hasKnownIssueWithinLimits
    {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        burn(targetAcc, amount);
        uint256 balanceAfter = ousd.balanceOf(target);

        Debugger.log("balanceBefore", balanceBefore);
        Debugger.log("balanceAfter", balanceAfter);

        assert(balanceAfter <= balanceBefore - amount);
    }

    /**
     * @notice Minting tokens should not increase the account balance by less than rounding error above amount
     * @param targetAcc Account to mint to
     * @param amount Amount to mint
     */
    function testMintBalanceRounding(uint8 targetAcc, uint256 amount) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        uint256 amountMinted = mint(targetAcc, amount);
        uint256 balanceAfter = ousd.balanceOf(target);

        int256 delta = int256(balanceAfter) - int256(balanceBefore);

        // delta == amount, if no error
        // delta < amount,  if too little is minted
        // delta > amount,  if too much is minted
        int256 error = int256(amountMinted) - delta;

        assert(error >= 0);
        assert(error <= int256(MINT_ROUNDING_ERROR));
    }

    /**
     * @notice A burn of an account balance must result in a zero balance
     * @param targetAcc Account to burn from
     */
    function testBurnAllBalanceToZero(uint8 targetAcc) public hasKnownIssue {
        address target = getAccount(targetAcc);

        burn(targetAcc, ousd.balanceOf(target));
        assert(ousd.balanceOf(target) == 0);
    }

    /**
     * @notice You should always be able to burn an account's balance
     * @param targetAcc Account to burn from
     */
    function testBurnAllBalanceShouldNotRevert(uint8 targetAcc)
        public
        hasKnownIssue
    {
        address target = getAccount(targetAcc);
        uint256 balance = ousd.balanceOf(target);

        hevm.prank(ADDRESS_VAULT);
        try ousd.burn(target, balance) {
            assert(true);
        } catch {
            assert(false);
        }
    }
}

95% contracts/contracts/echidna/EchidnaTestSupply.sol

Lines covered: 39 / 41 (95%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaDebug.sol";
import "./EchidnaTestTransfer.sol";

import { StableMath } from "../utils/StableMath.sol";

/**
 * @title Mixin for testing supply related functions
 * @author Rappie
 */
contract EchidnaTestSupply is EchidnaTestTransfer {
    using StableMath for uint256;

    uint256 prevRebasingCreditsPerToken = type(uint256).max;

    /**
     * @notice After a `changeSupply`, the total supply should exactly
     * match the target total supply. (This is needed to ensure successive
     * rebases are correct).
     * @param supply New total supply
     * @custom:error testChangeSupply(uint256): failed!💥
     *   Call sequence:
     *       testChangeSupply(1044505275072865171609)
     *   Event sequence:
     *       TotalSupplyUpdatedHighres(1044505275072865171610, 1000000000000000000000000, 957391048054055578595)
     */
    function testChangeSupply(uint256 supply)
        public
        hasKnownIssue
        hasKnownIssueWithinLimits
    {
        hevm.prank(ADDRESS_VAULT);
        ousd.changeSupply(supply);

        assert(ousd.totalSupply() == supply);
    }

    /**
     * @notice The total supply must not be less than the sum of account balances.
     * (The difference will go into future rebases)
     * @custom:error testTotalSupplyLessThanTotalBalance(): failed!💥
     *   Call sequence:
     *     mint(0,1)
     *     changeSupply(1)
     *     optOut(64)
     *     transfer(0,64,1)
     *     testTotalSupplyLessThanTotalBalance()
     *   Event sequence:
     *     Debug(«totalSupply», 1000000000000000001000001)
     *     Debug(«totalBalance», 1000000000000000001000002)
     */
    function testTotalSupplyLessThanTotalBalance()
        public
        hasKnownIssue
        hasKnownIssueWithinLimits
    {
        uint256 totalSupply = ousd.totalSupply();
        uint256 totalBalance = getTotalBalance();

        Debugger.log("totalSupply", totalSupply);
        Debugger.log("totalBalance", totalBalance);

        assert(totalSupply >= totalBalance);
    }

    /**
     * @notice Non-rebasing supply should not be larger than total supply
     * @custom:error testNonRebasingSupplyVsTotalSupply(): failed!💥
     *   Call sequence:
     *     mint(0,2)
     *     changeSupply(3)
     *     burn(0,1)
     *     optOut(0)
     *     testNonRebasingSupplyVsTotalSupply()
     */
    function testNonRebasingSupplyVsTotalSupply() public hasKnownIssue {
        uint256 nonRebasingSupply = ousd.nonRebasingSupply();
        uint256 totalSupply = ousd.totalSupply();

        assert(nonRebasingSupply <= totalSupply);
    }

    /**
     * @notice Global `rebasingCreditsPerToken` should never increase
     * @custom:error testRebasingCreditsPerTokenNotIncreased(): failed!💥
     *   Call sequence:
     *     testRebasingCreditsPerTokenNotIncreased()
     *     changeSupply(1)
     *     testRebasingCreditsPerTokenNotIncreased()
     */
    function testRebasingCreditsPerTokenNotIncreased() public hasKnownIssue {
        uint256 curRebasingCreditsPerToken = ousd
            .rebasingCreditsPerTokenHighres();

        Debugger.log(
            "prevRebasingCreditsPerToken",
            prevRebasingCreditsPerToken
        );
        Debugger.log("curRebasingCreditsPerToken", curRebasingCreditsPerToken);

        assert(curRebasingCreditsPerToken <= prevRebasingCreditsPerToken);

        prevRebasingCreditsPerToken = curRebasingCreditsPerToken;
    }

    /**
     * @notice The rebasing credits per token ratio must greater than zero
     */
    function testRebasingCreditsPerTokenAboveZero() public {
        assert(ousd.rebasingCreditsPerTokenHighres() > 0);
    }

    /**
     * @notice The sum of all non-rebasing balances should not be larger than
     * non-rebasing supply
     * @custom:error testTotalNonRebasingSupplyLessThanTotalBalance(): failed!💥
     *   Call sequence
     *     mint(0,2)
     *     changeSupply(1)
     *     optOut(0)
     *     burn(0,1)
     *     testTotalNonRebasingSupplyLessThanTotalBalance()
     *   Event sequence:
     *     Debug(«totalNonRebasingSupply», 500000000000000000000001)
     *     Debug(«totalNonRebasingBalance», 500000000000000000000002)
     */
    function testTotalNonRebasingSupplyLessThanTotalBalance()
        public
        hasKnownIssue
        hasKnownIssueWithinLimits
    {
        uint256 totalNonRebasingSupply = ousd.nonRebasingSupply();
        uint256 totalNonRebasingBalance = getTotalNonRebasingBalance();

        Debugger.log("totalNonRebasingSupply", totalNonRebasingSupply);
        Debugger.log("totalNonRebasingBalance", totalNonRebasingBalance);

        assert(totalNonRebasingSupply >= totalNonRebasingBalance);
    }

    /**
     * @notice An accounts credits / credits per token should not be larger it's balance
     * @param targetAcc The account to check
     */
    function testCreditsPerTokenVsBalance(uint8 targetAcc) public {
        address target = getAccount(targetAcc);

        (uint256 credits, uint256 creditsPerToken, ) = ousd
            .creditsBalanceOfHighres(target);
        uint256 expectedBalance = credits.divPrecisely(creditsPerToken);

        uint256 balance = ousd.balanceOf(target);

        Debugger.log("credits", credits);
        Debugger.log("creditsPerToken", creditsPerToken);
        Debugger.log("expectedBalance", expectedBalance);
        Debugger.log("balance", balance);

        assert(expectedBalance == balance);
    }
}

96% contracts/contracts/echidna/EchidnaTestTransfer.sol

Lines covered: 103 / 107 (96%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "./EchidnaDebug.sol";
import "./Debugger.sol";

/**
 * @title Mixin for testing transfer related functions
 * @author Rappie
 */
contract EchidnaTestTransfer is EchidnaDebug {
    /**
     * @notice The receiving account's balance after a transfer must not increase by
     * less than the amount transferred
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     * @custom:error testTransferBalanceReceivedLess(uint8,uint8,uint256): failed!💥
     *   Call sequence:
     *     changeSupply(1)
     *     mint(64,2)
     *     testTransferBalanceReceivedLess(64,0,1)
     *   Event sequence:
     *     Debug(«totalSupply», 1000000000000000000500002)
     *     Debug(«toBalBefore», 0)
     *     Debug(«toBalAfter», 0)
     */
    function testTransferBalanceReceivedLess(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public hasKnownIssue hasKnownIssueWithinLimits {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 toBalBefore = ousd.balanceOf(to);
        transfer(fromAcc, toAcc, amount);
        uint256 toBalAfter = ousd.balanceOf(to);

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("toBalBefore", toBalBefore);
        Debugger.log("toBalAfter", toBalAfter);

        assert(toBalAfter >= toBalBefore + amount);
    }

    /**
     * @notice The receiving account's balance after a transfer must not
     * increase by more than the amount transferred
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferBalanceReceivedMore(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 toBalBefore = ousd.balanceOf(to);
        transfer(fromAcc, toAcc, amount);
        uint256 toBalAfter = ousd.balanceOf(to);

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("toBalBefore", toBalBefore);
        Debugger.log("toBalAfter", toBalAfter);

        assert(toBalAfter <= toBalBefore + amount);
    }

    /**
     * @notice The sending account's balance after a transfer must not
     * decrease by less than the amount transferred
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     * @custom:error testTransferBalanceSentLess(uint8,uint8,uint256): failed!💥
     *   Call sequence:
     *     mint(0,1)
     *     changeSupply(1)
     *     testTransferBalanceSentLess(0,64,1)
     *   Event sequence:
     *     Debug(«totalSupply», 1000000000000000000500001)
     *     Debug(«fromBalBefore», 1)
     *     Debug(«fromBalAfter», 1)
     */
    function testTransferBalanceSentLess(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public hasKnownIssue hasKnownIssueWithinLimits {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 fromBalBefore = ousd.balanceOf(from);
        transfer(fromAcc, toAcc, amount);
        uint256 fromBalAfter = ousd.balanceOf(from);

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("fromBalBefore", fromBalBefore);
        Debugger.log("fromBalAfter", fromBalAfter);

        assert(fromBalAfter <= fromBalBefore - amount);
    }

    /**
     * @notice The sending account's balance after a transfer must not
     * decrease by more than the amount transferred
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferBalanceSentMore(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 fromBalBefore = ousd.balanceOf(from);
        transfer(fromAcc, toAcc, amount);
        uint256 fromBalAfter = ousd.balanceOf(from);

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("fromBalBefore", fromBalBefore);
        Debugger.log("fromBalAfter", fromBalAfter);

        assert(fromBalAfter >= fromBalBefore - amount);
    }

    /**
     * @notice The receiving account's balance after a transfer must not
     * increase by less than the amount transferred (minus rounding error)
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferBalanceReceivedLessRounding(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 toBalBefore = ousd.balanceOf(to);
        transfer(fromAcc, toAcc, amount);
        uint256 toBalAfter = ousd.balanceOf(to);

        int256 toDelta = int256(toBalAfter) - int256(toBalBefore);

        // delta == amount, if no error
        // delta < amount,  if too little is sent
        // delta > amount,  if too much is sent
        int256 error = int256(amount) - toDelta;

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("toBalBefore", toBalBefore);
        Debugger.log("toBalAfter", toBalAfter);
        Debugger.log("toDelta", toDelta);
        Debugger.log("error", error);

        assert(error >= 0);
        assert(error <= int256(TRANSFER_ROUNDING_ERROR));
    }

    /**
     * @notice The sending account's balance after a transfer must
     * not decrease by less than the amount transferred (minus rounding error)
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferBalanceSentLessRounding(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(from != to);

        uint256 fromBalBefore = ousd.balanceOf(from);
        transfer(fromAcc, toAcc, amount);
        uint256 fromBalAfter = ousd.balanceOf(from);

        int256 fromDelta = int256(fromBalAfter) - int256(fromBalBefore);

        // delta == -amount, if no error
        // delta < -amount,  if too much is sent
        // delta > -amount,  if too little is sent
        int256 error = int256(amount) + fromDelta;

        Debugger.log("totalSupply", ousd.totalSupply());
        Debugger.log("fromBalBefore", fromBalBefore);
        Debugger.log("fromBalAfter", fromBalAfter);
        Debugger.log("fromDelta", fromDelta);
        Debugger.log("error", error);

        assert(error >= 0);
        assert(error <= int256(TRANSFER_ROUNDING_ERROR));
    }

    /**
     * @notice An account should always be able to successfully transfer
     * an amount within its balance.
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     * @custom:error testTransferWithinBalanceDoesNotRevert(uint8,uint8,uint8): failed!💥
     *   Call sequence:
     *       mint(0,1)
     *       changeSupply(3)
     *       optOut(0)
     *       testTransferWithinBalanceDoesNotRevert(0,128,2)
     *       optIn(0)
     *       testTransferWithinBalanceDoesNotRevert(128,0,1)
     *   Event sequence:
     *       error Revert Panic(17): SafeMath over-/under-flows
     */
    function testTransferWithinBalanceDoesNotRevert(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public hasKnownIssue {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        require(amount > 0);
        amount = amount % ousd.balanceOf(from);

        Debugger.log("Total supply", ousd.totalSupply());

        hevm.prank(from);
        // slither-disable-next-line unchecked-transfer
        try ousd.transfer(to, amount) {
            assert(true);
        } catch {
            assert(false);
        }
    }

    /**
     * @notice An account should never be able to successfully transfer
     * an amount greater than their balance.
     * @param fromAcc Account to transfer from
     * @param toAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferExceedingBalanceReverts(
        uint8 fromAcc,
        uint8 toAcc,
        uint256 amount
    ) public {
        address from = getAccount(fromAcc);
        address to = getAccount(toAcc);

        amount = ousd.balanceOf(from) + 1 + amount;

        hevm.prank(from);
        // slither-disable-next-line unchecked-transfer
        try ousd.transfer(to, amount) {
            assert(false);
        } catch {
            assert(true);
        }
    }

    /**
     * @notice A transfer to the same account should not change that account's balance
     * @param targetAcc Account to transfer to
     * @param amount Amount to transfer
     */
    function testTransferSelf(uint8 targetAcc, uint256 amount) public {
        address target = getAccount(targetAcc);

        uint256 balanceBefore = ousd.balanceOf(target);
        transfer(targetAcc, targetAcc, amount);
        uint256 balanceAfter = ousd.balanceOf(target);

        assert(balanceBefore == balanceAfter);
    }

    /**
     * @notice Transfers to the zero account revert
     * @param fromAcc Account to transfer from
     * @param amount Amount to transfer
     */
    function testTransferToZeroAddress(uint8 fromAcc, uint256 amount) public {
        address from = getAccount(fromAcc);

        hevm.prank(from);
        // slither-disable-next-line unchecked-transfer
        try ousd.transfer(address(0), amount) {
            assert(false);
        } catch {
            assert(true);
        }
    }
}

100% contracts/contracts/echidna/OUSDEchidna.sol

Lines covered: 7 / 7 (100%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import "../token/OUSD.sol";

contract OUSDEchidna is OUSD {
    constructor() OUSD() {
        // The Yield Delegation rewrite (#2298) left Governable without a
        // constructor, so the governor slot is zero and the harness could
        // never call initialize() (onlyGovernor). Make the deploying harness
        // the governor so the suite is runnable again.
        _setGovernor(msg.sender);
    }

    function _isNonRebasingAccountEchidna(address _account)
        public
        returns (bool)
    {
        _autoMigrate(_account);
        return alternativeCreditsPerToken[_account] > 0;
    }
}

29% contracts/contracts/governance/Governable.sol

Lines covered: 7 / 24 (29%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

/**
 * @title Base for contracts that are managed by the Origin Protocol's Governor.
 * @dev Copy of the openzeppelin Ownable.sol contract with nomenclature change
 *      from owner to governor and renounce methods removed. Does not use
 *      Context.sol like Ownable.sol does for simplification.
 * @author Origin Protocol Inc
 */
abstract contract Governable {
    // Storage position of the owner and pendingOwner of the contract
    // keccak256("OUSD.governor");
    bytes32 private constant governorPosition =
        0x7bea13895fa79d2831e0a9e28edede30099005a50d652d8957cf8a607ee6ca4a;

    // keccak256("OUSD.pending.governor");
    bytes32 private constant pendingGovernorPosition =
        0x44c4d30b2eaad5130ad70c3ba6972730566f3e6359ab83e800d905c61b1c51db;

    // keccak256("OUSD.reentry.status");
    bytes32 private constant reentryStatusPosition =
        0x53bf423e48ed90e97d02ab0ebab13b2a235a6bfbe9c321847d5c175333ac4535;

    // See OpenZeppelin ReentrancyGuard implementation
    uint256 constant _NOT_ENTERED = 1;
    uint256 constant _ENTERED = 2;

    event PendingGovernorshipTransfer(
        address indexed previousGovernor,
        address indexed newGovernor
    );

    event GovernorshipTransferred(
        address indexed previousGovernor,
        address indexed newGovernor
    );

    /**
     * @notice Returns the address of the current Governor.
     */
    function governor() public view returns (address) {
        return _governor();
    }

    /**
     * @dev Returns the address of the current Governor.
     */
    function _governor() internal view returns (address governorOut) {
        bytes32 position = governorPosition;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            governorOut := sload(position)
        }
    }

    /**
     * @dev Returns the address of the pending Governor.
     */
    function _pendingGovernor()
        internal
        view
        returns (address pendingGovernor)
    {
        bytes32 position = pendingGovernorPosition;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            pendingGovernor := sload(position)
        }
    }

    /**
     * @dev Throws if called by any account other than the Governor.
     */
    modifier onlyGovernor() {
        require(isGovernor(), "Caller is not the Governor");
        _;
    }

    /**
     * @notice Returns true if the caller is the current Governor.
     */
    function isGovernor() public view returns (bool) {
        return msg.sender == _governor();
    }

    function _setGovernor(address newGovernor) internal {
        emit GovernorshipTransferred(_governor(), newGovernor);

        bytes32 position = governorPosition;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(position, newGovernor)
        }
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        bytes32 position = reentryStatusPosition;
        uint256 _reentry_status;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            _reentry_status := sload(position)
        }

        // On the first call to nonReentrant, _notEntered will be true
        require(_reentry_status != _ENTERED, "Reentrant call");

        // Any calls to nonReentrant after this point will fail
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(position, _ENTERED)
        }

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(position, _NOT_ENTERED)
        }
    }

    function _setPendingGovernor(address newGovernor) internal {
        bytes32 position = pendingGovernorPosition;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(position, newGovernor)
        }
    }

    /**
     * @notice Transfers Governance of the contract to a new account (`newGovernor`).
     * Can only be called by the current Governor. Must be claimed for this to complete
     * @param _newGovernor Address of the new Governor
     */
    function transferGovernance(address _newGovernor) external onlyGovernor {
        _setPendingGovernor(_newGovernor);
        emit PendingGovernorshipTransfer(_governor(), _newGovernor);
    }

    /**
     * @notice Claim Governance of the contract to a new account (`newGovernor`).
     * Can only be called by the new Governor.
     */
    function claimGovernance() external {
        require(
            msg.sender == _pendingGovernor(),
            "Only the pending Governor can complete the claim"
        );
        _changeGovernor(msg.sender);
    }

    /**
     * @dev Change Governance of the contract to a new account (`newGovernor`).
     * @param _newGovernor Address of the new Governor
     */
    function _changeGovernor(address _newGovernor) internal {
        require(_newGovernor != address(0), "New Governor is address(0)");
        _setGovernor(_newGovernor);
    }
}

61% contracts/contracts/token/OUSD.sol

Lines covered: 176 / 284 (61%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

/**
 * @title OUSD Token Contract
 * @dev ERC20 compatible contract for OUSD
 * @dev Implements an elastic supply
 * @author Origin Protocol Inc
 */
import { IVault } from "../interfaces/IVault.sol";
import { Governable } from "../governance/Governable.sol";
import { SafeCast } from "@openzeppelin/contracts/utils/math/SafeCast.sol";

contract OUSD is Governable {
    using SafeCast for int256;
    using SafeCast for uint256;

    /// @dev Event triggered when the supply changes
    /// @param totalSupply Updated token total supply
    /// @param rebasingCredits Updated token rebasing credits
    /// @param rebasingCreditsPerToken Updated token rebasing credits per token
    event TotalSupplyUpdatedHighres(
        uint256 totalSupply,
        uint256 rebasingCredits,
        uint256 rebasingCreditsPerToken
    );
    /// @dev Event triggered when an account opts in for rebasing
    /// @param account Address of the account
    event AccountRebasingEnabled(address account);
    /// @dev Event triggered when an account opts out of rebasing
    /// @param account Address of the account
    event AccountRebasingDisabled(address account);
    /// @dev Emitted when `value` tokens are moved from one account `from` to
    ///      another `to`.
    /// @param from Address of the account tokens are moved from
    /// @param to Address of the account tokens are moved to
    /// @param value Amount of tokens transferred
    event Transfer(address indexed from, address indexed to, uint256 value);
    /// @dev Emitted when the allowance of a `spender` for an `owner` is set by
    ///      a call to {approve}. `value` is the new allowance.
    /// @param owner Address of the owner approving allowance
    /// @param spender Address of the spender allowance is granted to
    /// @param value Amount of tokens spender can transfer
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
    /// @dev Yield resulting from {changeSupply} that a `source` account would
    ///      receive is directed to `target` account.
    /// @param source Address of the source forwarding the yield
    /// @param target Address of the target receiving the yield
    event YieldDelegated(address source, address target);
    /// @dev Yield delegation from `source` account to the `target` account is
    ///      suspended.
    /// @param source Address of the source suspending yield forwarding
    /// @param target Address of the target no longer receiving yield from `source`
    ///        account
    event YieldUndelegated(address source, address target);

    enum RebaseOptions {
        NotSet,
        StdNonRebasing,
        StdRebasing,
        YieldDelegationSource,
        YieldDelegationTarget
    }

    uint256[154] private _gap; // Slots to align with deployed contract
    uint256 private constant MAX_SUPPLY = type(uint128).max;
    /// @dev The amount of tokens in existence
    uint256 public totalSupply;
    mapping(address => mapping(address => uint256)) private allowances;
    /// @dev The vault with privileges to execute {mint}, {burn}
    ///     and {changeSupply}
    address public vaultAddress;
    mapping(address => uint256) internal creditBalances;
    // the 2 storage variables below need trailing underscores to not name collide with public functions
    uint256 private rebasingCredits_; // Sum of all rebasing credits (creditBalances for rebasing accounts)
    uint256 private rebasingCreditsPerToken_;
    /// @dev The amount of tokens that are not rebasing - receiving yield
    uint256 public nonRebasingSupply;
    mapping(address => uint256) internal alternativeCreditsPerToken;
    /// @dev A map of all addresses and their respective RebaseOptions
    mapping(address => RebaseOptions) public rebaseState;
    mapping(address => uint256) private __deprecated_isUpgraded;
    /// @dev A map of addresses that have yields forwarded to. This is an
    ///      inverse mapping of {yieldFrom}
    /// Key Account forwarding yield
    /// Value Account receiving yield
    mapping(address => address) public yieldTo;
    /// @dev A map of addresses that are receiving the yield. This is an
    ///      inverse mapping of {yieldTo}
    /// Key Account receiving yield
    /// Value Account forwarding yield
    mapping(address => address) public yieldFrom;

    uint256 private constant RESOLUTION_INCREASE = 1e9;
    uint256[34] private __gap; // including below gap totals up to 200

    /// @dev Verifies that the caller is the Governor or Strategist.
    modifier onlyGovernorOrStrategist() {
        require(
            isGovernor() || msg.sender == IVault(vaultAddress).strategistAddr(),
            "Caller is not the Strategist or Governor"
        );
        _;
    }

    /// @dev Initializes the contract and sets necessary variables.
    /// @param _vaultAddress Address of the vault contract
    /// @param _initialCreditsPerToken The starting rebasing credits per token.
    function initialize(address _vaultAddress, uint256 _initialCreditsPerToken)
        external
        onlyGovernor
    {
        require(_vaultAddress != address(0), "Zero vault address");
        require(vaultAddress == address(0), "Already initialized");

        rebasingCreditsPerToken_ = _initialCreditsPerToken;
        vaultAddress = _vaultAddress;
    }

    /// @dev Returns the symbol of the token, a shorter version
    ///      of the name.
    function symbol() external pure virtual returns (string memory) {
        return "OUSD";
    }

    /// @dev Returns the name of the token.
    function name() external pure virtual returns (string memory) {
        return "Origin Dollar";
    }

    /// @dev Returns the number of decimals used to get its user representation.
    function decimals() external pure virtual returns (uint8) {
        return 18;
    }

    /**
     * @dev Verifies that the caller is the Vault contract
     */
    modifier onlyVault() {
        require(vaultAddress == msg.sender, "Caller is not the Vault");
        _;
    }

    /**
     * @return High resolution rebasingCreditsPerToken
     */
    function rebasingCreditsPerTokenHighres() external view returns (uint256) {
        return rebasingCreditsPerToken_;
    }

    /**
     * @return Low resolution rebasingCreditsPerToken
     */
    function rebasingCreditsPerToken() external view returns (uint256) {
        return rebasingCreditsPerToken_ / RESOLUTION_INCREASE;
    }

    /**
     * @return High resolution total number of rebasing credits
     */
    function rebasingCreditsHighres() external view returns (uint256) {
        return rebasingCredits_;
    }

    /**
     * @return Low resolution total number of rebasing credits
     */
    function rebasingCredits() external view returns (uint256) {
        return rebasingCredits_ / RESOLUTION_INCREASE;
    }

    /**
     * @notice Gets the balance of the specified address.
     * @param _account Address to query the balance of.
     * @return A uint256 representing the amount of base units owned by the
     *         specified address.
     */
    function balanceOf(address _account) public view returns (uint256) {
        RebaseOptions state = rebaseState[_account];
        if (state == RebaseOptions.YieldDelegationSource) {
            // Saves a slot read when transferring to or from a yield delegating source
            // since we know creditBalances equals the balance.
            return creditBalances[_account];
        }
        uint256 baseBalance = (creditBalances[_account] * 1e18) /
            _creditsPerToken(_account);
        if (state == RebaseOptions.YieldDelegationTarget) {
            // creditBalances of yieldFrom accounts equals token balances
            return baseBalance - creditBalances[yieldFrom[_account]];
        }
        return baseBalance;
    }

    /**
     * @notice Gets the credits balance of the specified address.
     * @dev Backwards compatible with old low res credits per token.
     * @param _account The address to query the balance of.
     * @return (uint256, uint256) Credit balance and credits per token of the
     *         address
     */
    function creditsBalanceOf(address _account)
        external
        view
        returns (uint256, uint256)
    {
        uint256 cpt = _creditsPerToken(_account);
        if (cpt == 1e27) {
            // For a period before the resolution upgrade, we created all new
            // contract accounts at high resolution. Since they are not changing
            // as a result of this upgrade, we will return their true values
            return (creditBalances[_account], cpt);
        } else {
            return (
                creditBalances[_account] / RESOLUTION_INCREASE,
                cpt / RESOLUTION_INCREASE
            );
        }
    }

    /**
     * @notice Gets the credits balance of the specified address.
     * @param _account The address to query the balance of.
     * @return (uint256, uint256, bool) Credit balance, credits per token of the
     *         address, and isUpgraded
     */
    function creditsBalanceOfHighres(address _account)
        external
        view
        returns (
            uint256,
            uint256,
            bool
        )
    {
        return (
            creditBalances[_account],
            _creditsPerToken(_account),
            true // all accounts have their resolution "upgraded"
        );
    }

    // Backwards compatible view
    function nonRebasingCreditsPerToken(address _account)
        external
        view
        returns (uint256)
    {
        return alternativeCreditsPerToken[_account];
    }

    /**
     * @notice Transfer tokens to a specified address.
     * @param _to the address to transfer to.
     * @param _value the amount to be transferred.
     * @return true on success.
     */
    function transfer(address _to, uint256 _value) external returns (bool) {
        require(_to != address(0), "Transfer to zero address");

        _executeTransfer(msg.sender, _to, _value);

        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
     * @notice Transfer tokens from one address to another.
     * @param _from The address you want to send tokens from.
     * @param _to The address you want to transfer to.
     * @param _value The amount of tokens to be transferred.
     * @return true on success.
     */
    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    ) external returns (bool) {
        require(_to != address(0), "Transfer to zero address");
        uint256 userAllowance = allowances[_from][msg.sender];
        require(_value <= userAllowance, "Allowance exceeded");

        unchecked {
            allowances[_from][msg.sender] = userAllowance - _value;
        }

        _executeTransfer(_from, _to, _value);

        emit Transfer(_from, _to, _value);
        return true;
    }

    function _executeTransfer(
        address _from,
        address _to,
        uint256 _value
    ) internal {
        (
            int256 fromRebasingCreditsDiff,
            int256 fromNonRebasingSupplyDiff
        ) = _adjustAccount(_from, -_value.toInt256());
        (
            int256 toRebasingCreditsDiff,
            int256 toNonRebasingSupplyDiff
        ) = _adjustAccount(_to, _value.toInt256());

        _adjustGlobals(
            fromRebasingCreditsDiff + toRebasingCreditsDiff,
            fromNonRebasingSupplyDiff + toNonRebasingSupplyDiff
        );
    }

    function _adjustAccount(address _account, int256 _balanceChange)
        internal
        returns (int256 rebasingCreditsDiff, int256 nonRebasingSupplyDiff)
    {
        RebaseOptions state = rebaseState[_account];
        int256 currentBalance = balanceOf(_account).toInt256();
        if (currentBalance + _balanceChange < 0) {
            revert("Transfer amount exceeds balance");
        }
        uint256 newBalance = (currentBalance + _balanceChange).toUint256();

        if (state == RebaseOptions.YieldDelegationSource) {
            address target = yieldTo[_account];
            uint256 targetOldBalance = balanceOf(target);
            uint256 targetNewCredits = _balanceToRebasingCredits(
                targetOldBalance + newBalance
            );
            rebasingCreditsDiff =
                targetNewCredits.toInt256() -
                creditBalances[target].toInt256();

            creditBalances[_account] = newBalance;
            creditBalances[target] = targetNewCredits;
        } else if (state == RebaseOptions.YieldDelegationTarget) {
            uint256 newCredits = _balanceToRebasingCredits(
                newBalance + creditBalances[yieldFrom[_account]]
            );
            rebasingCreditsDiff =
                newCredits.toInt256() -
                creditBalances[_account].toInt256();
            creditBalances[_account] = newCredits;
        } else {
            _autoMigrate(_account);
            uint256 alternativeCreditsPerTokenMem = alternativeCreditsPerToken[
                _account
            ];
            if (alternativeCreditsPerTokenMem > 0) {
                nonRebasingSupplyDiff = _balanceChange;
                if (alternativeCreditsPerTokenMem != 1e18) {
                    alternativeCreditsPerToken[_account] = 1e18;
                }
                creditBalances[_account] = newBalance;
            } else {
                uint256 newCredits = _balanceToRebasingCredits(newBalance);
                rebasingCreditsDiff =
                    newCredits.toInt256() -
                    creditBalances[_account].toInt256();
                creditBalances[_account] = newCredits;
            }
        }
    }

    function _adjustGlobals(
        int256 _rebasingCreditsDiff,
        int256 _nonRebasingSupplyDiff
    ) internal {
        if (_rebasingCreditsDiff != 0) {
            rebasingCredits_ = (rebasingCredits_.toInt256() +
                _rebasingCreditsDiff).toUint256();
        }
        if (_nonRebasingSupplyDiff != 0) {
            nonRebasingSupply = (nonRebasingSupply.toInt256() +
                _nonRebasingSupplyDiff).toUint256();
        }
    }

    /**
     * @notice Function to check the amount of tokens that _owner has allowed
     *      to `_spender`.
     * @param _owner The address which owns the funds.
     * @param _spender The address which will spend the funds.
     * @return The number of tokens still available for the _spender.
     */
    function allowance(address _owner, address _spender)
        external
        view
        returns (uint256)
    {
        return allowances[_owner][_spender];
    }

    /**
     * @notice Approve the passed address to spend the specified amount of
     *      tokens on behalf of msg.sender.
     * @param _spender The address which will spend the funds.
     * @param _value The amount of tokens to be spent.
     * @return true on success.
     */
    function approve(address _spender, uint256 _value) external returns (bool) {
        allowances[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    /**
     * @notice Creates `_amount` tokens and assigns them to `_account`,
     *     increasing the total supply.
     */
    function mint(address _account, uint256 _amount) external onlyVault {
        require(_account != address(0), "Mint to the zero address");

        // Account
        (
            int256 toRebasingCreditsDiff,
            int256 toNonRebasingSupplyDiff
        ) = _adjustAccount(_account, _amount.toInt256());
        // Globals
        _adjustGlobals(toRebasingCreditsDiff, toNonRebasingSupplyDiff);
        totalSupply = totalSupply + _amount;

        require(totalSupply < MAX_SUPPLY, "Max supply");
        emit Transfer(address(0), _account, _amount);
    }

    /**
     * @notice Destroys `_amount` tokens from `_account`,
     *     reducing the total supply.
     */
    function burn(address _account, uint256 _amount) external onlyVault {
        require(_account != address(0), "Burn from the zero address");
        if (_amount == 0) {
            return;
        }

        // Account
        (
            int256 toRebasingCreditsDiff,
            int256 toNonRebasingSupplyDiff
        ) = _adjustAccount(_account, -_amount.toInt256());
        // Globals
        _adjustGlobals(toRebasingCreditsDiff, toNonRebasingSupplyDiff);
        totalSupply = totalSupply - _amount;

        emit Transfer(_account, address(0), _amount);
    }

    /**
     * @dev Get the credits per token for an account. Returns a fixed amount
     *      if the account is non-rebasing.
     * @param _account Address of the account.
     */
    function _creditsPerToken(address _account)
        internal
        view
        returns (uint256)
    {
        uint256 alternativeCreditsPerTokenMem = alternativeCreditsPerToken[
            _account
        ];
        if (alternativeCreditsPerTokenMem != 0) {
            return alternativeCreditsPerTokenMem;
        } else {
            return rebasingCreditsPerToken_;
        }
    }

    /**
     * @dev Auto migrate contracts to be non rebasing,
     *     unless they have opted into yield.
     * @param _account Address of the account.
     */
    function _autoMigrate(address _account) internal {
        uint256 codeLen = _account.code.length;
        bool isEOA = (codeLen == 0) ||
            (codeLen == 23 && bytes3(_account.code) == 0xef0100);
        // In previous code versions, contracts would not have had their
        // rebaseState[_account] set to RebaseOptions.NonRebasing when migrated
        // therefore we check the actual accounting used on the account as well.
        if (
            (!isEOA) &&
            rebaseState[_account] == RebaseOptions.NotSet &&
            alternativeCreditsPerToken[_account] == 0
        ) {
            _rebaseOptOut(_account);
        }
    }

    /**
     * @dev Calculates credits from contract's global rebasingCreditsPerToken_, and
     *      also balance that corresponds to those credits. The latter is important
     *      when adjusting the contract's global nonRebasingSupply to circumvent any
     *      possible rounding errors.
     *
     * @param _balance Balance of the account.
     */
    function _balanceToRebasingCredits(uint256 _balance)
        internal
        view
        returns (uint256 rebasingCredits)
    {
        // Rounds up, because we need to ensure that accounts always have
        // at least the balance that they should have.
        // Note this should always be used on an absolute account value,
        // not on a possibly negative diff, because then the rounding would be wrong.
        return ((_balance) * rebasingCreditsPerToken_ + 1e18 - 1) / 1e18;
    }

    /**
     * @notice The calling account will start receiving yield after a successful call.
     * @param _account Address of the account.
     */
    function governanceRebaseOptIn(address _account) external onlyGovernor {
        require(_account != address(0), "Zero address not allowed");
        _rebaseOptIn(_account);
    }

    /**
     * @notice The calling account will start receiving yield after a successful call.
     */
    function rebaseOptIn() external {
        _rebaseOptIn(msg.sender);
    }

    function _rebaseOptIn(address _account) internal {
        uint256 balance = balanceOf(_account);

        // prettier-ignore
        require(
            alternativeCreditsPerToken[_account] > 0 ||
                // Accounts may explicitly `rebaseOptIn` regardless of
                // accounting if they have a 0 balance.
                creditBalances[_account] == 0
            ,
            "Account must be non-rebasing"
        );
        RebaseOptions state = rebaseState[_account];
        // prettier-ignore
        require(
            state == RebaseOptions.StdNonRebasing ||
                state == RebaseOptions.NotSet,
            "Only standard non-rebasing accounts can opt in"
        );

        uint256 newCredits = _balanceToRebasingCredits(balance);

        // Account
        rebaseState[_account] = RebaseOptions.StdRebasing;
        alternativeCreditsPerToken[_account] = 0;
        creditBalances[_account] = newCredits;
        // Globals
        _adjustGlobals(newCredits.toInt256(), -balance.toInt256());

        emit AccountRebasingEnabled(_account);
    }

    /**
     * @notice The calling account will no longer receive yield
     */
    function rebaseOptOut() external {
        _rebaseOptOut(msg.sender);
    }

    function _rebaseOptOut(address _account) internal {
        require(
            alternativeCreditsPerToken[_account] == 0,
            "Account must be rebasing"
        );
        RebaseOptions state = rebaseState[_account];
        require(
            state == RebaseOptions.StdRebasing || state == RebaseOptions.NotSet,
            "Only standard rebasing accounts can opt out"
        );

        uint256 oldCredits = creditBalances[_account];
        uint256 balance = balanceOf(_account);

        // Account
        rebaseState[_account] = RebaseOptions.StdNonRebasing;
        alternativeCreditsPerToken[_account] = 1e18;
        creditBalances[_account] = balance;
        // Globals
        _adjustGlobals(-oldCredits.toInt256(), balance.toInt256());

        emit AccountRebasingDisabled(_account);
    }

    /**
     * @notice Distribute yield to users. This changes the exchange rate
     *  between "credits" and OUSD tokens to change rebasing user's balances.
     * @param _newTotalSupply New total supply of OUSD.
     */
    function changeSupply(uint256 _newTotalSupply) external onlyVault {
        require(totalSupply > 0, "Cannot increase 0 supply");

        if (totalSupply == _newTotalSupply) {
            emit TotalSupplyUpdatedHighres(
                totalSupply,
                rebasingCredits_,
                rebasingCreditsPerToken_
            );
            return;
        }

        totalSupply = _newTotalSupply > MAX_SUPPLY
            ? MAX_SUPPLY
            : _newTotalSupply;

        uint256 rebasingSupply = totalSupply - nonRebasingSupply;
        // round up in the favour of the protocol
        rebasingCreditsPerToken_ =
            (rebasingCredits_ * 1e18 + rebasingSupply - 1) /
            rebasingSupply;

        require(rebasingCreditsPerToken_ > 0, "Invalid change in supply");

        emit TotalSupplyUpdatedHighres(
            totalSupply,
            rebasingCredits_,
            rebasingCreditsPerToken_
        );
    }

    /*
     * @notice Send the yield from one account to another account.
     *         Each account keeps its own balances.
     */
    function delegateYield(address _from, address _to)
        external
        onlyGovernorOrStrategist
    {
        require(_from != address(0), "Zero from address not allowed");
        require(_to != address(0), "Zero to address not allowed");

        require(_from != _to, "Cannot delegate to self");
        require(
            yieldFrom[_to] == address(0) &&
                yieldTo[_to] == address(0) &&
                yieldFrom[_from] == address(0) &&
                yieldTo[_from] == address(0),
            "Blocked by existing yield delegation"
        );
        RebaseOptions stateFrom = rebaseState[_from];
        RebaseOptions stateTo = rebaseState[_to];

        require(
            stateFrom == RebaseOptions.NotSet ||
                stateFrom == RebaseOptions.StdNonRebasing ||
                stateFrom == RebaseOptions.StdRebasing,
            "Invalid rebaseState from"
        );

        require(
            stateTo == RebaseOptions.NotSet ||
                stateTo == RebaseOptions.StdNonRebasing ||
                stateTo == RebaseOptions.StdRebasing,
            "Invalid rebaseState to"
        );

        if (alternativeCreditsPerToken[_from] == 0) {
            _rebaseOptOut(_from);
        }
        if (alternativeCreditsPerToken[_to] > 0) {
            _rebaseOptIn(_to);
        }

        uint256 fromBalance = balanceOf(_from);
        uint256 toBalance = balanceOf(_to);
        uint256 oldToCredits = creditBalances[_to];
        uint256 newToCredits = _balanceToRebasingCredits(
            fromBalance + toBalance
        );

        // Set up the bidirectional links
        yieldTo[_from] = _to;
        yieldFrom[_to] = _from;

        // Local
        rebaseState[_from] = RebaseOptions.YieldDelegationSource;
        alternativeCreditsPerToken[_from] = 1e18;
        creditBalances[_from] = fromBalance;
        rebaseState[_to] = RebaseOptions.YieldDelegationTarget;
        creditBalances[_to] = newToCredits;

        // Global
        int256 creditsChange = newToCredits.toInt256() -
            oldToCredits.toInt256();
        _adjustGlobals(creditsChange, -(fromBalance).toInt256());
        emit YieldDelegated(_from, _to);
    }

    /*
     * @notice Stop sending the yield from one account to another account.
     */
    function undelegateYield(address _from) external onlyGovernorOrStrategist {
        // Require a delegation, which will also ensure a valid delegation
        require(yieldTo[_from] != address(0), "Zero address not allowed");

        address to = yieldTo[_from];
        uint256 fromBalance = balanceOf(_from);
        uint256 toBalance = balanceOf(to);
        uint256 oldToCredits = creditBalances[to];
        uint256 newToCredits = _balanceToRebasingCredits(toBalance);

        // Remove the bidirectional links
        yieldFrom[to] = address(0);
        yieldTo[_from] = address(0);

        // Local
        rebaseState[_from] = RebaseOptions.StdNonRebasing;
        // alternativeCreditsPerToken[from] already 1e18 from `delegateYield()`
        creditBalances[_from] = fromBalance;
        rebaseState[to] = RebaseOptions.StdRebasing;
        // alternativeCreditsPerToken[to] already 0 from `delegateYield()`
        creditBalances[to] = newToCredits;

        // Global
        int256 creditsChange = newToCredits.toInt256() -
            oldToCredits.toInt256();
        _adjustGlobals(creditsChange, fromBalance.toInt256());
        emit YieldUndelegated(_from, to);
    }
}

83% contracts/contracts/utils/StableMath.sol

Lines covered: 5 / 6 (83%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import { SafeMath } from "@openzeppelin/contracts/utils/math/SafeMath.sol";

// Based on StableMath from Stability Labs Pty. Ltd.
// https://github.com/mstable/mStable-contracts/blob/master/contracts/shared/StableMath.sol

library StableMath {
    using SafeMath for uint256;

    /**
     * @dev Scaling unit for use in specific calculations,
     * where 1 * 10**18, or 1e18 represents a unit '1'
     */
    uint256 private constant FULL_SCALE = 1e18;

    /***************************************
                    Helpers
    ****************************************/

    /**
     * @dev Adjust the scale of an integer
     * @param to Decimals to scale to
     * @param from Decimals to scale from
     */
    function scaleBy(
        uint256 x,
        uint256 to,
        uint256 from
    ) internal pure returns (uint256) {
        if (to > from) {
            x = x.mul(10**(to - from));
        } else if (to < from) {
            // slither-disable-next-line divide-before-multiply
            x = x.div(10**(from - to));
        }
        return x;
    }

    /***************************************
               Precise Arithmetic
    ****************************************/

    /**
     * @dev Multiplies two precise units, and then truncates by the full scale
     * @param x Left hand input to multiplication
     * @param y Right hand input to multiplication
     * @return Result after multiplying the two inputs and then dividing by the shared
     *         scale unit
     */
    function mulTruncate(uint256 x, uint256 y) internal pure returns (uint256) {
        return mulTruncateScale(x, y, FULL_SCALE);
    }

    /**
     * @dev Multiplies two precise units, and then truncates by the given scale. For example,
     * when calculating 90% of 10e18, (10e18 * 9e17) / 1e18 = (9e36) / 1e18 = 9e18
     * @param x Left hand input to multiplication
     * @param y Right hand input to multiplication
     * @param scale Scale unit
     * @return Result after multiplying the two inputs and then dividing by the shared
     *         scale unit
     */
    function mulTruncateScale(
        uint256 x,
        uint256 y,
        uint256 scale
    ) internal pure returns (uint256) {
        // e.g. assume scale = fullScale
        // z = 10e18 * 9e17 = 9e36
        uint256 z = x.mul(y);
        // return 9e36 / 1e18 = 9e18
        return z.div(scale);
    }

    /**
     * @dev Multiplies two precise units, and then truncates by the full scale, rounding up the result
     * @param x Left hand input to multiplication
     * @param y Right hand input to multiplication
     * @return Result after multiplying the two inputs and then dividing by the shared
     *          scale unit, rounded up to the closest base unit.
     */
    function mulTruncateCeil(uint256 x, uint256 y)
        internal
        pure
        returns (uint256)
    {
        // e.g. 8e17 * 17268172638 = 138145381104e17
        uint256 scaled = x.mul(y);
        // e.g. 138145381104e17 + 9.99...e17 = 138145381113.99...e17
        uint256 ceil = scaled.add(FULL_SCALE.sub(1));
        // e.g. 13814538111.399...e18 / 1e18 = 13814538111
        return ceil.div(FULL_SCALE);
    }

    /**
     * @dev Precisely divides two units, by first scaling the left hand operand. Useful
     *      for finding percentage weightings, i.e. 8e18/10e18 = 80% (or 8e17)
     * @param x Left hand input to division
     * @param y Right hand input to division
     * @return Result after multiplying the left operand by the scale, and
     *         executing the division on the right hand input.
     */
    function divPrecisely(uint256 x, uint256 y)
        internal
        pure
        returns (uint256)
    {
        // e.g. 8e18 * 1e18 = 8e36
        uint256 z = x.mul(FULL_SCALE);
        // e.g. 8e36 / 10e18 = 8e17
        return z.div(y);
    }
}

83% lib/openzeppelin-contracts/contracts/utils/math/SafeCast.sol

Lines covered: 5 / 6 (83%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SafeCast.sol)

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such an operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {
    /**
     * @dev Returns the downcasted uint224 from uint256, reverting on
     * overflow (when the input is greater than largest uint224).
     *
     * Counterpart to Solidity's `uint224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     */
    function toUint224(uint256 value) internal pure returns (uint224) {
        require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
        return uint224(value);
    }

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint96 from uint256, reverting on
     * overflow (when the input is greater than largest uint96).
     *
     * Counterpart to Solidity's `uint96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     */
    function toUint96(uint256 value) internal pure returns (uint96) {
        require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
        return uint96(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128) {
        require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
        return int128(value);
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64) {
        require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
        return int64(value);
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32) {
        require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
        return int32(value);
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16) {
        require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
        return int16(value);
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8) {
        require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
        return int8(value);
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
        require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}

80% lib/openzeppelin-contracts/contracts/utils/math/SafeMath.sol

Lines covered: 4 / 5 (80%)

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

100% test/recon/CryticTester.sol

Lines covered: 1 / 1 (100%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import {Properties} from "./Properties.sol";

// echidna test/recon/CryticTester.sol --contract CryticTester --config echidna.yaml
contract CryticTester is Properties {}

88% test/recon/Properties.sol

Lines covered: 8 / 9 (88%)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import {Echidna} from "../../contracts/contracts/echidna/Echidna.sol";

/// @notice scfuzzbench adaptation layer: canary checks on top of the
/// upstream OUSD Echidna suite. Assertion failures are surfaced the same
/// way for Echidna, Medusa, Foundry, and Recon (AssertionFailed event +
/// assert), and dedup to the emitting function name across fuzzers.
abstract contract Properties is Echidna {
    string internal constant ASSERTION_CANARY = "!!! canary assertion";
    string internal constant INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE = "Canary invariant";

    event AssertionFailed(string reason);

    function t(bool b, string memory reason) internal {
        if (!b) {
            emit AssertionFailed(reason);
            assert(false);
        }
    }

    function invariant_canary() public returns (bool) {
        t(false, INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE);
        return true;
    }

    function assert_canary_ASSERTION_CANARY(uint256 entropy) public {
        t(entropy > 0, ASSERTION_CANARY);
    }
}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4	0	library Debugger {
5		event Debug(string debugString);
6		event Debug(string description, string data);
7		event Debug(string prefix, string description, string data);
8		event Debug(string description, bytes32 data);
9		event Debug(string prefix, string description, bytes32 data);
10		event Debug(string description, uint256 data);
11		event Debug(string prefix, string description, uint256 data);
12		event Debug(string description, int256 data);
13		event Debug(string prefix, string description, int256 data);
14		event Debug(string description, address data);
15		event Debug(string prefix, string description, address data);
16		event Debug(string description, bool data);
17		event Debug(string prefix, string description, bool data);
18
19		function log(string memory debugString) internal {
20		emit Debug(debugString);
21		}
22
23		function log(string memory description, string memory data) internal {
24		emit Debug(description, data);
25		}
26
27		function log(
28		string memory prefix,
29		string memory description,
30		string memory data
31		) internal {
32		emit Debug(prefix, description, data);
33		}
34
35		function log(string memory description, bytes32 data) internal {
36		emit Debug(description, data);
37		}
38
39		function log(
40		string memory prefix,
41		string memory description,
42		bytes32 data
43		) internal {
44		emit Debug(prefix, description, data);
45		}
46
47	8×	function log(string memory description, uint256 data) internal {
48	38×	emit Debug(description, data);
49		}
50
51		function log(
52		string memory prefix,
53		string memory description,
54		uint256 data
55		) internal {
56		emit Debug(prefix, description, data);
57		}
58
59	1×	function log(string memory description, int256 data) internal {
60	11×	emit Debug(description, data);
61		}
62
63		function log(
64		string memory prefix,
65		string memory description,
66		int256 data
67		) internal {
68		emit Debug(prefix, description, data);
69		}
70
71		function log(string memory description, address data) internal {
72		emit Debug(description, data);
73		}
74
75		function log(
76		string memory prefix,
77		string memory description,
78		address data
79		) internal {
80		emit Debug(prefix, description, data);
81		}
82
83		function log(string memory description, bool data) internal {
84		emit Debug(description, data);
85		}
86
87		function log(
88		string memory prefix,
89		string memory description,
90		bool data
91		) internal {
92		emit Debug(prefix, description, data);
93		}
94		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		/**
5		* @title Top-level mixin for configuring the desired fuzzing setup
6		* @author Rappie
7		*/
8	0	contract EchidnaConfig {
9	10×	address internal constant ADDRESS_VAULT = address(0x10000);
10	3×	address internal constant ADDRESS_OUTSIDER_USER = address(0x20000);
11
12	7×	address internal constant ADDRESS_USER0 = address(0x30000);
13	7×	address internal constant ADDRESS_USER1 = address(0x40000);
14
15		// Will be set in EchidnaSetup constructor
16		address internal ADDRESS_OUTSIDER_CONTRACT;
17		address internal ADDRESS_CONTRACT0;
18		address internal ADDRESS_CONTRACT1;
19
20		// Toggle known issues
21		//
22		// This can be used to skip tests that are known to fail. This is useful
23		// when debugging a specific issue, but should be disabled when running
24		// the full test suite.
25		//
26		// True => skip tests that are known to fail
27		// False => run all tests
28		//
29		bool internal constant TOGGLE_KNOWN_ISSUES = false;
30
31		// Toggle known issues within limits
32		//
33		// Same as TOGGLE_KNOWN_ISSUES, but also skip tests that are known to fail
34		// within limits set by the variables below.
35		//
36		bool internal constant TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS = false;
37
38		// Starting balance
39		//
40		// Gives OUSD a non-zero starting supply, which can be useful to ignore
41		// certain edge cases.
42		//
43		// The starting balance is given to outsider accounts that are not used as
44		// accounts while fuzzing.
45		//
46		bool internal constant TOGGLE_STARTING_BALANCE = true;
47	2×	uint256 internal constant STARTING_BALANCE = 1_000_000e18;
48
49		// Change supply
50		//
51		// Set a limit to the amount of change per rebase, which can be useful to
52		// ignore certain edge cases.
53		//
54		// True => limit the amount of change to a percentage of total supply
55		// False => no limit
56		//
57		bool internal constant TOGGLE_CHANGESUPPLY_LIMIT = true;
58	1×	uint256 internal constant CHANGESUPPLY_DIVISOR = 10; // 10% of total supply
59
60		// Mint limit
61		//
62		// Set a limit the amount minted per mint, which can be useful to
63		// ignore certain edge cases.
64		//
65		// True => limit the amount of minted tokens
66		// False => no limit
67		//
68		bool internal constant TOGGLE_MINT_LIMIT = true;
69	1×	uint256 internal constant MINT_MODULO = 1_000_000_000_000e18;
70
71		// Known rounding errors
72	1×	uint256 internal constant TRANSFER_ROUNDING_ERROR = 1e18 - 1;
73	1×	uint256 internal constant OPT_IN_ROUNDING_ERROR = 1e18 - 1;
74	1×	uint256 internal constant MINT_ROUNDING_ERROR = 1e18 - 1;
75
76		/**
77		* @notice Modifier to skip tests that are known to fail
78		* @dev see TOGGLE_KNOWN_ISSUES for more information
79		*/
80		modifier hasKnownIssue() {
81		if (TOGGLE_KNOWN_ISSUES) return;
82	5×	_;
83		}
84
85		/**
86		* @notice Modifier to skip tests that are known to fail within limits
87		* @dev see TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS for more information
88		*/
89		modifier hasKnownIssueWithinLimits() {
90		if (TOGGLE_KNOWN_ISSUES_WITHIN_LIMITS) return;
91		_;
92		}
93
94		/**
95		* @notice Translate an account ID to an address
96		* @param accountId The ID of the account
97		* @return account The address of the account
98		*/
99	22×	function getAccount(uint8 accountId)
100		internal
101		view
102	2×	returns (address account)
103		{
104	16×	accountId = accountId / 64;
105	16×	if (accountId == 0) return account = ADDRESS_USER0;
106	16×	if (accountId == 1) return account = ADDRESS_USER1;
107	24×	if (accountId == 2) return account = ADDRESS_CONTRACT0;
108	22×	if (accountId == 3) return account = ADDRESS_CONTRACT1;
109	2×	require(false, "Unknown account ID");
110		}
111		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import "./EchidnaSetup.sol";
5		import "./Debugger.sol";
6
7		/**
8		* @title Mixin containing helper functions
9		* @author Rappie
10		*/
11	0	contract EchidnaHelper is EchidnaSetup {
12		/**
13		* @notice Mint tokens to an account
14		* @param toAcc Account to mint to
15		* @param amount Amount to mint
16		* @return Amount minted (in case of capped mint with modulo)
17		*/
18	24×	function mint(uint8 toAcc, uint256 amount) public returns (uint256) {
19	7×	address to = getAccount(toAcc);
20
21		if (TOGGLE_MINT_LIMIT) {
22	7×	amount = amount % MINT_MODULO;
23		}
24
25	39×	hevm.prank(ADDRESS_VAULT);
26	52×	ousd.mint(to, amount);
27
28	4×	return amount;
29		}
30
31		/**
32		* @notice Burn tokens from an account
33		* @param fromAcc Account to burn from
34		* @param amount Amount to burn
35		*/
36	11×	function burn(uint8 fromAcc, uint256 amount) public {
37	8×	address from = getAccount(fromAcc);
38	39×	hevm.prank(ADDRESS_VAULT);
39	47×	ousd.burn(from, amount);
40		}
41
42		/**
43		* @notice Change the total supply of OUSD (rebase)
44		* @param amount New total supply
45		*/
46	11×	function changeSupply(uint256 amount) public {
47		if (TOGGLE_CHANGESUPPLY_LIMIT) {
48	2×	amount =
49	71×	ousd.totalSupply() +
50	79×	(amount % (ousd.totalSupply() / CHANGESUPPLY_DIVISOR));
51		}
52
53	39×	hevm.prank(ADDRESS_VAULT);
54	46×	ousd.changeSupply(amount);
55		}
56
57		/**
58		* @notice Transfer tokens between accounts
59		* @param fromAcc Account to transfer from
60		* @param toAcc Account to transfer to
61		* @param amount Amount to transfer
62		*/
63	11×	function transfer(
64		uint8 fromAcc,
65		uint8 toAcc,
66		uint256 amount
67	0	) public {
68	8×	address from = getAccount(fromAcc);
69	8×	address to = getAccount(toAcc);
70	40×	hevm.prank(from);
71		// slither-disable-next-line unchecked-transfer
72	67×	ousd.transfer(to, amount);
73		}
74
75		/**
76		* @notice Transfer approved tokens between accounts
77		* @param authorizedAcc Account that is authorized to transfer
78		* @param fromAcc Account to transfer from
79		* @param toAcc Account to transfer to
80		* @param amount Amount to transfer
81		*/
82	16×	function transferFrom(
83		uint8 authorizedAcc,
84		uint8 fromAcc,
85		uint8 toAcc,
86		uint256 amount
87	3×	) public {
88	8×	address authorized = getAccount(authorizedAcc);
89	8×	address from = getAccount(fromAcc);
90	8×	address to = getAccount(toAcc);
91	40×	hevm.prank(authorized);
92		// slither-disable-next-line unchecked-transfer
93	68×	ousd.transferFrom(from, to, amount);
94		}
95
96		/**
97		* @notice Opt in to rebasing
98		* @param targetAcc Account to opt in
99		*/
100	11×	function optIn(uint8 targetAcc) public {
101	8×	address target = getAccount(targetAcc);
102	40×	hevm.prank(target);
103	37×	ousd.rebaseOptIn();
104		}
105
106		/**
107		* @notice Opt out of rebasing
108		* @param targetAcc Account to opt out
109		*/
110	11×	function optOut(uint8 targetAcc) public {
111	8×	address target = getAccount(targetAcc);
112	40×	hevm.prank(target);
113	53×	ousd.rebaseOptOut();
114		}
115
116		/**
117		* @notice Approve an account to spend OUSD
118		* @param ownerAcc Account that owns the OUSD
119		* @param spenderAcc Account that is approved to spend the OUSD
120		* @param amount Amount to approve
121		*/
122	15×	function approve(
123		uint8 ownerAcc,
124		uint8 spenderAcc,
125		uint256 amount
126		) public {
127	16×	address owner = getAccount(ownerAcc);
128	16×	address spender = getAccount(spenderAcc);
129	74×	hevm.prank(owner);
130		// slither-disable-next-line unused-return
131	16×	ousd.approve(spender, amount);
132		}
133
134		/**
135		* @notice Get the sum of all OUSD balances
136		* @return total Total balance
137		*/
138	27×	function getTotalBalance() public view returns (uint256 total) {
139	68×	total += ousd.balanceOf(ADDRESS_VAULT);
140	68×	total += ousd.balanceOf(ADDRESS_OUTSIDER_USER);
141	74×	total += ousd.balanceOf(ADDRESS_OUTSIDER_CONTRACT);
142	68×	total += ousd.balanceOf(ADDRESS_USER0);
143	68×	total += ousd.balanceOf(ADDRESS_USER1);
144	74×	total += ousd.balanceOf(ADDRESS_CONTRACT0);
145	75×	total += ousd.balanceOf(ADDRESS_CONTRACT1);
146		}
147
148		/**
149		* @notice Get the sum of all non-rebasing OUSD balances
150		* @return total Total balance
151		*/
152	7×	function getTotalNonRebasingBalance() public returns (uint256 total) {
153	73×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_VAULT)
154	1×	? ousd.balanceOf(ADDRESS_VAULT)
155	1×	: 0;
156	73×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_OUTSIDER_USER)
157	1×	? ousd.balanceOf(ADDRESS_OUTSIDER_USER)
158	1×	: 0;
159	78×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_OUTSIDER_CONTRACT)
160	63×	? ousd.balanceOf(ADDRESS_OUTSIDER_CONTRACT)
161	0	: 0;
162	74×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_USER0)
163	58×	? ousd.balanceOf(ADDRESS_USER0)
164	1×	: 0;
165	74×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_USER1)
166	58×	? ousd.balanceOf(ADDRESS_USER1)
167	1×	: 0;
168	80×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_CONTRACT0)
169	63×	? ousd.balanceOf(ADDRESS_CONTRACT0)
170	1×	: 0;
171	72×	total += ousd._isNonRebasingAccountEchidna(ADDRESS_CONTRACT1)
172	20×	? ousd.balanceOf(ADDRESS_CONTRACT1)
173	1×	: 0;
174		}
175		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import "./IHevm.sol";
5		import "./EchidnaConfig.sol";
6		import "./OUSDEchidna.sol";
7
8	17×	contract Dummy {}
9
10		/**
11		* @title Mixin for setup and deployment
12		* @author Rappie
13		*/
14	0	contract EchidnaSetup is EchidnaConfig {
15	8×	IHevm hevm = IHevm(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
16	34×	OUSDEchidna ousd = new OUSDEchidna();
17
18		/**
19		* @notice Deploy the OUSD contract and set up initial state
20		*/
21	3×	constructor() {
22	45×	ousd.initialize(ADDRESS_VAULT, 1e18);
23
24		// Deploy dummny contracts as users
25	23×	Dummy outsider = new Dummy();
26	12×	ADDRESS_OUTSIDER_CONTRACT = address(outsider);
27	22×	Dummy dummy0 = new Dummy();
28	11×	ADDRESS_CONTRACT0 = address(dummy0);
29	22×	Dummy dummy1 = new Dummy();
30	16×	ADDRESS_CONTRACT1 = address(dummy1);
31
32		// Start out with a reasonable amount of OUSD
33		if (TOGGLE_STARTING_BALANCE) {
34		// Rebasing tokens
35	39×	hevm.prank(ADDRESS_VAULT);
36	49×	ousd.mint(ADDRESS_OUTSIDER_USER, STARTING_BALANCE / 2);
37
38		// Non-rebasing tokens
39	41×	hevm.prank(ADDRESS_VAULT);
40	58×	ousd.mint(ADDRESS_OUTSIDER_CONTRACT, STARTING_BALANCE / 2);
41		}
42		}
43		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import "./EchidnaDebug.sol";
5		import "./EchidnaTestSupply.sol";
6
7		/**
8		* @title Mixin for testing accounting functions
9		* @author Rappie
10		*/
11	0	contract EchidnaTestAccounting is EchidnaTestSupply {
12		/**
13		* @notice After opting in, balance should not increase. (Ok to lose rounding funds doing this)
14		* @param targetAcc Account to opt in
15		*/
16	11×	function testOptInBalance(uint8 targetAcc) public {
17	8×	address target = getAccount(targetAcc);
18
19	63×	uint256 balanceBefore = ousd.balanceOf(target);
20	5×	optIn(targetAcc);
21	64×	uint256 balanceAfter = ousd.balanceOf(target);
22
23	9×	assert(balanceAfter <= balanceBefore);
24		}
25
26		/**
27		* @notice After opting out, balance should remain the same
28		* @param targetAcc Account to opt out
29		*/
30	11×	function testOptOutBalance(uint8 targetAcc) public {
31	8×	address target = getAccount(targetAcc);
32
33	63×	uint256 balanceBefore = ousd.balanceOf(target);
34	5×	optOut(targetAcc);
35	19×	uint256 balanceAfter = ousd.balanceOf(target);
36
37		assert(balanceAfter == balanceBefore);
38		}
39
40		/**
41		* @notice Account balance should remain the same after opting in minus rounding error
42		* @param targetAcc Account to opt in
43		*/
44	11×	function testOptInBalanceRounding(uint8 targetAcc) public {
45	8×	address target = getAccount(targetAcc);
46
47	63×	uint256 balanceBefore = ousd.balanceOf(target);
48	5×	optIn(targetAcc);
49	64×	uint256 balanceAfter = ousd.balanceOf(target);
50
51	8×	int256 delta = int256(balanceAfter) - int256(balanceBefore);
52	21×	Debugger.log("delta", delta);
53
54		// slither-disable-next-line tautology
55	14×	assert(-1 * delta >= 0);
56	9×	assert(-1 * delta <= int256(OPT_IN_ROUNDING_ERROR));
57		}
58
59		/**
60		* @notice After opting in, total supply should remain the same
61		* @param targetAcc Account to opt in
62		*/
63	11×	function testOptInTotalSupply(uint8 targetAcc) public {
64	70×	uint256 totalSupplyBefore = ousd.totalSupply();
65	4×	optIn(targetAcc);
66		uint256 totalSupplyAfter = ousd.totalSupply();
67
68		assert(totalSupplyAfter == totalSupplyBefore);
69		}
70
71		/**
72		* @notice After opting out, total supply should remain the same
73		* @param targetAcc Account to opt out
74		*/
75	11×	function testOptOutTotalSupply(uint8 targetAcc) public {
76	70×	uint256 totalSupplyBefore = ousd.totalSupply();
77	5×	optOut(targetAcc);
78	70×	uint256 totalSupplyAfter = ousd.totalSupply();
79
80	5×	assert(totalSupplyAfter == totalSupplyBefore);
81		}
82
83		/**
84		* @notice Account balance should remain the same when a smart contract auto converts
85		* @param targetAcc Account to auto convert
86		*/
87	21×	function testAutoConvertBalance(uint8 targetAcc) public {
88	8×	address target = getAccount(targetAcc);
89
90	63×	uint256 balanceBefore = ousd.balanceOf(target);
91		// slither-disable-next-line unused-return
92	60×	ousd._isNonRebasingAccountEchidna(target);
93	130×	uint256 balanceAfter = ousd.balanceOf(target);
94
95	12×	assert(balanceAfter == balanceBefore);
96		}
97
98		/**
99		* @notice The `balanceOf` function should never revert
100		* @param targetAcc Account to check balance of
101		*/
102	11×	function testBalanceOfShouldNotRevert(uint8 targetAcc) public {
103	8×	address target = getAccount(targetAcc);
104
105		// slither-disable-next-line unused-return
106	58×	try ousd.balanceOf(target) {
107	0	assert(true);
108		} catch {
109	0	assert(false);
110		}
111		}
112		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import "./EchidnaTestMintBurn.sol";
5		import "./Debugger.sol";
6
7		/**
8		* @title Mixin for testing approval related functions
9		* @author Rappie
10		*/
11	0	contract EchidnaTestApproval is EchidnaTestMintBurn {
12		/**
13		* @notice Performing `transferFrom` with an amount inside the allowance should not revert
14		* @param authorizedAcc The account that is authorized to transfer
15		* @param fromAcc The account that is transferring
16		* @param toAcc The account that is receiving
17		* @param amount The amount to transfer
18		*/
19	11×	function testTransferFromShouldNotRevert(
20		uint8 authorizedAcc,
21		uint8 fromAcc,
22		uint8 toAcc,
23		uint256 amount
24		) public {
25	8×	address authorized = getAccount(authorizedAcc);
26	8×	address from = getAccount(fromAcc);
27	8×	address to = getAccount(toAcc);
28
29	67×	require(amount <= ousd.balanceOf(from));
30	68×	require(amount <= ousd.allowance(from, authorized));
31
32	41×	hevm.prank(authorized);
33		// slither-disable-next-line unchecked-transfer
34	60×	try ousd.transferFrom(from, to, amount) {
35		// pass
36		} catch {
37	3×	assert(false);
38		}
39		}
40
41		/**
42		* @notice Performing `transferFrom` with an amount outside the allowance should revert
43		* @param authorizedAcc The account that is authorized to transfer
44		* @param fromAcc The account that is transferring
45		* @param toAcc The account that is receiving
46		* @param amount The amount to transfer
47		*/
48	16×	function testTransferFromShouldRevert(
49		uint8 authorizedAcc,
50		uint8 fromAcc,
51		uint8 toAcc,
52		uint256 amount
53	3×	) public {
54	8×	address authorized = getAccount(authorizedAcc);
55	8×	address from = getAccount(fromAcc);
56	8×	address to = getAccount(toAcc);
57
58	9×	require(amount > 0);
59	6×	require(
60	68×	!(amount <= ousd.balanceOf(from) &&
61	62×	amount <= ousd.allowance(from, authorized))
62		);
63
64	41×	hevm.prank(authorized);
65		// slither-disable-next-line unchecked-transfer
66	38×	try ousd.transferFrom(from, to, amount) {
67	1×	assert(false);
68		} catch {
69		// pass
70		}
71		}
72
73		/**
74		* @notice Approving an amount should update the allowance and overwrite any previous allowance
75		* @param ownerAcc The account that is approving
76		* @param spenderAcc The account that is being approved
77		* @param amount The amount to approve
78		*/
79	11×	function testApprove(
80		uint8 ownerAcc,
81		uint8 spenderAcc,
82		uint256 amount
83		) public {
84	8×	address owner = getAccount(ownerAcc);
85	8×	address spender = getAccount(spenderAcc);
86
87	7×	approve(ownerAcc, spenderAcc, amount);
88	64×	uint256 allowanceAfter1 = ousd.allowance(owner, spender);
89
90	6×	assert(allowanceAfter1 == amount);
91
92	9×	approve(ownerAcc, spenderAcc, amount / 2);
93	63×	uint256 allowanceAfter2 = ousd.allowance(owner, spender);
94
95	10×	assert(allowanceAfter2 == amount / 2);
96		}
97		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import "../token/OUSD.sol";
5
6	277×	contract OUSDEchidna is OUSD {
7	6×	constructor() OUSD() {
8		// The Yield Delegation rewrite (#2298) left Governable without a
9		// constructor, so the governor slot is zero and the harness could
10		// never call initialize() (onlyGovernor). Make the deploying harness
11		// the governor so the suite is runnable again.
12	5×	_setGovernor(msg.sender);
13		}
14
15	12×	function _isNonRebasingAccountEchidna(address _account)
16		public
17	1×	returns (bool)
18		{
19	5×	_autoMigrate(_account);
20	15×	return alternativeCreditsPerToken[_account] > 0;
21		}
22		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		/**
5		* @title Base for contracts that are managed by the Origin Protocol's Governor.
6		* @dev Copy of the openzeppelin Ownable.sol contract with nomenclature change
7		* from owner to governor and renounce methods removed. Does not use
8		* Context.sol like Ownable.sol does for simplification.
9		* @author Origin Protocol Inc
10		*/
11		abstract contract Governable {
12		// Storage position of the owner and pendingOwner of the contract
13		// keccak256("OUSD.governor");
14		bytes32 private constant governorPosition =
15		0x7bea13895fa79d2831e0a9e28edede30099005a50d652d8957cf8a607ee6ca4a;
16
17		// keccak256("OUSD.pending.governor");
18		bytes32 private constant pendingGovernorPosition =
19	0	0x44c4d30b2eaad5130ad70c3ba6972730566f3e6359ab83e800d905c61b1c51db;
20
21		// keccak256("OUSD.reentry.status");
22		bytes32 private constant reentryStatusPosition =
23		0x53bf423e48ed90e97d02ab0ebab13b2a235a6bfbe9c321847d5c175333ac4535;
24
25		// See OpenZeppelin ReentrancyGuard implementation
26		uint256 constant _NOT_ENTERED = 1;
27		uint256 constant _ENTERED = 2;
28
29		event PendingGovernorshipTransfer(
30		address indexed previousGovernor,
31		address indexed newGovernor
32		);
33
34		event GovernorshipTransferred(
35		address indexed previousGovernor,
36		address indexed newGovernor
37		);
38
39		/**
40		* @notice Returns the address of the current Governor.
41		*/
42	0	function governor() public view returns (address) {
43	0	return _governor();
44		}
45
46		/**
47		* @dev Returns the address of the current Governor.
48		*/
49	1×	function _governor() internal view returns (address governorOut) {
50		bytes32 position = governorPosition;
51		// solhint-disable-next-line no-inline-assembly
52		assembly {
53	2×	governorOut := sload(position)
54		}
55		}
56
57		/**
58		* @dev Returns the address of the pending Governor.
59		*/
60		function _pendingGovernor()
61		internal
62		view
63		returns (address pendingGovernor)
64		{
65		bytes32 position = pendingGovernorPosition;
66		// solhint-disable-next-line no-inline-assembly
67		assembly {
68	0	pendingGovernor := sload(position)
69		}
70		}
71
72		/**
73		* @dev Throws if called by any account other than the Governor.
74		*/
75		modifier onlyGovernor() {
76	0	require(isGovernor(), "Caller is not the Governor");
77		_;
78		}
79
80		/**
81		* @notice Returns true if the caller is the current Governor.
82		*/
83	0	function isGovernor() public view returns (bool) {
84	0	return msg.sender == _governor();
85		}
86
87	2×	function _setGovernor(address newGovernor) internal {
88	15×	emit GovernorshipTransferred(_governor(), newGovernor);
89
90		bytes32 position = governorPosition;
91		// solhint-disable-next-line no-inline-assembly
92		assembly {
93	1×	sstore(position, newGovernor)
94		}
95		}
96
97		/**
98		* @dev Prevents a contract from calling itself, directly or indirectly.
99		* Calling a `nonReentrant` function from another `nonReentrant`
100		* function is not supported. It is possible to prevent this from happening
101		* by making the `nonReentrant` function external, and make it call a
102		* `private` function that does the actual work.
103		*/
104		modifier nonReentrant() {
105		bytes32 position = reentryStatusPosition;
106		uint256 _reentry_status;
107		// solhint-disable-next-line no-inline-assembly
108		assembly {
109		_reentry_status := sload(position)
110		}
111
112		// On the first call to nonReentrant, _notEntered will be true
113		require(_reentry_status != _ENTERED, "Reentrant call");
114
115		// Any calls to nonReentrant after this point will fail
116		// solhint-disable-next-line no-inline-assembly
117		assembly {
118		sstore(position, _ENTERED)
119		}
120
121		_;
122
123		// By storing the original value once again, a refund is triggered (see
124		// https://eips.ethereum.org/EIPS/eip-2200)
125		// solhint-disable-next-line no-inline-assembly
126		assembly {
127		sstore(position, _NOT_ENTERED)
128		}
129		}
130
131	0	function _setPendingGovernor(address newGovernor) internal {
132		bytes32 position = pendingGovernorPosition;
133		// solhint-disable-next-line no-inline-assembly
134		assembly {
135	0	sstore(position, newGovernor)
136		}
137		}
138
139		/**
140		* @notice Transfers Governance of the contract to a new account (`newGovernor`).
141		* Can only be called by the current Governor. Must be claimed for this to complete
142		* @param _newGovernor Address of the new Governor
143		*/
144	0	function transferGovernance(address _newGovernor) external onlyGovernor {
145	0	_setPendingGovernor(_newGovernor);
146	0	emit PendingGovernorshipTransfer(_governor(), _newGovernor);
147		}
148
149		/**
150		* @notice Claim Governance of the contract to a new account (`newGovernor`).
151		* Can only be called by the new Governor.
152		*/
153	1×	function claimGovernance() external {
154	0	require(
155	0	msg.sender == _pendingGovernor(),
156		"Only the pending Governor can complete the claim"
157		);
158	1×	_changeGovernor(msg.sender);
159		}
160
161		/**
162		* @dev Change Governance of the contract to a new account (`newGovernor`).
163		* @param _newGovernor Address of the new Governor
164		*/
165	0	function _changeGovernor(address _newGovernor) internal {
166	0	require(_newGovernor != address(0), "New Governor is address(0)");
167	0	_setGovernor(_newGovernor);
168		}
169		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import { SafeMath } from "@openzeppelin/contracts/utils/math/SafeMath.sol";
5
6		// Based on StableMath from Stability Labs Pty. Ltd.
7		// https://github.com/mstable/mStable-contracts/blob/master/contracts/shared/StableMath.sol
8
9	0	library StableMath {
10		using SafeMath for uint256;
11
12		/**
13		* @dev Scaling unit for use in specific calculations,
14		* where 1 * 10**18, or 1e18 represents a unit '1'
15		*/
16	1×	uint256 private constant FULL_SCALE = 1e18;
17
18		/***************************************
19		Helpers
20		****************************************/
21
22		/**
23		* @dev Adjust the scale of an integer
24		* @param to Decimals to scale to
25		* @param from Decimals to scale from
26		*/
27		function scaleBy(
28		uint256 x,
29		uint256 to,
30		uint256 from
31		) internal pure returns (uint256) {
32		if (to > from) {
33		x = x.mul(10**(to - from));
34		} else if (to < from) {
35		// slither-disable-next-line divide-before-multiply
36		x = x.div(10**(from - to));
37		}
38		return x;
39		}
40
41		/***************************************
42		Precise Arithmetic
43		****************************************/
44
45		/**
46		* @dev Multiplies two precise units, and then truncates by the full scale
47		* @param x Left hand input to multiplication
48		* @param y Right hand input to multiplication
49		* @return Result after multiplying the two inputs and then dividing by the shared
50		* scale unit
51		*/
52		function mulTruncate(uint256 x, uint256 y) internal pure returns (uint256) {
53		return mulTruncateScale(x, y, FULL_SCALE);
54		}
55
56		/**
57		* @dev Multiplies two precise units, and then truncates by the given scale. For example,
58		* when calculating 90% of 10e18, (10e18 * 9e17) / 1e18 = (9e36) / 1e18 = 9e18
59		* @param x Left hand input to multiplication
60		* @param y Right hand input to multiplication
61		* @param scale Scale unit
62		* @return Result after multiplying the two inputs and then dividing by the shared
63		* scale unit
64		*/
65		function mulTruncateScale(
66		uint256 x,
67		uint256 y,
68		uint256 scale
69		) internal pure returns (uint256) {
70		// e.g. assume scale = fullScale
71		// z = 10e18 * 9e17 = 9e36
72		uint256 z = x.mul(y);
73		// return 9e36 / 1e18 = 9e18
74		return z.div(scale);
75		}
76
77		/**
78		* @dev Multiplies two precise units, and then truncates by the full scale, rounding up the result
79		* @param x Left hand input to multiplication
80		* @param y Right hand input to multiplication
81		* @return Result after multiplying the two inputs and then dividing by the shared
82		* scale unit, rounded up to the closest base unit.
83		*/
84		function mulTruncateCeil(uint256 x, uint256 y)
85		internal
86		pure
87		returns (uint256)
88		{
89		// e.g. 8e17 * 17268172638 = 138145381104e17
90		uint256 scaled = x.mul(y);
91		// e.g. 138145381104e17 + 9.99...e17 = 138145381113.99...e17
92		uint256 ceil = scaled.add(FULL_SCALE.sub(1));
93		// e.g. 13814538111.399...e18 / 1e18 = 13814538111
94		return ceil.div(FULL_SCALE);
95		}
96
97		/**
98		* @dev Precisely divides two units, by first scaling the left hand operand. Useful
99		* for finding percentage weightings, i.e. 8e18/10e18 = 80% (or 8e17)
100		* @param x Left hand input to division
101		* @param y Right hand input to division
102		* @return Result after multiplying the left operand by the scale, and
103		* executing the division on the right hand input.
104		*/
105	3×	function divPrecisely(uint256 x, uint256 y)
106		internal
107		pure
108	2×	returns (uint256)
109		{
110		// e.g. 8e18 * 1e18 = 8e36
111	7×	uint256 z = x.mul(FULL_SCALE);
112		// e.g. 8e36 / 10e18 = 8e17
113	6×	return z.div(y);
114		}
115		}

1		// SPDX-License-Identifier: MIT
2		// OpenZeppelin Contracts v4.4.1 (utils/math/SafeCast.sol)
3
4		pragma solidity ^0.8.0;
5
6		/**
7		* @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
8		* checks.
9		*
10		* Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
11		* easily result in undesired exploitation or bugs, since developers usually
12		* assume that overflows raise errors. `SafeCast` restores this intuition by
13		* reverting the transaction when such an operation overflows.
14		*
15		* Using this library instead of the unchecked operations eliminates an entire
16		* class of bugs, so it's recommended to use it always.
17		*
18		* Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
19		* all math on `uint256` and `int256` and then downcasting.
20		*/
21	0	library SafeCast {
22		/**
23		* @dev Returns the downcasted uint224 from uint256, reverting on
24		* overflow (when the input is greater than largest uint224).
25		*
26		* Counterpart to Solidity's `uint224` operator.
27		*
28		* Requirements:
29		*
30		* - input must fit into 224 bits
31		*/
32		function toUint224(uint256 value) internal pure returns (uint224) {
33		require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
34		return uint224(value);
35		}
36
37		/**
38		* @dev Returns the downcasted uint128 from uint256, reverting on
39		* overflow (when the input is greater than largest uint128).
40		*
41		* Counterpart to Solidity's `uint128` operator.
42		*
43		* Requirements:
44		*
45		* - input must fit into 128 bits
46		*/
47		function toUint128(uint256 value) internal pure returns (uint128) {
48		require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
49		return uint128(value);
50		}
51
52		/**
53		* @dev Returns the downcasted uint96 from uint256, reverting on
54		* overflow (when the input is greater than largest uint96).
55		*
56		* Counterpart to Solidity's `uint96` operator.
57		*
58		* Requirements:
59		*
60		* - input must fit into 96 bits
61		*/
62		function toUint96(uint256 value) internal pure returns (uint96) {
63		require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
64		return uint96(value);
65		}
66
67		/**
68		* @dev Returns the downcasted uint64 from uint256, reverting on
69		* overflow (when the input is greater than largest uint64).
70		*
71		* Counterpart to Solidity's `uint64` operator.
72		*
73		* Requirements:
74		*
75		* - input must fit into 64 bits
76		*/
77		function toUint64(uint256 value) internal pure returns (uint64) {
78		require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
79		return uint64(value);
80		}
81
82		/**
83		* @dev Returns the downcasted uint32 from uint256, reverting on
84		* overflow (when the input is greater than largest uint32).
85		*
86		* Counterpart to Solidity's `uint32` operator.
87		*
88		* Requirements:
89		*
90		* - input must fit into 32 bits
91		*/
92		function toUint32(uint256 value) internal pure returns (uint32) {
93		require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
94		return uint32(value);
95		}
96
97		/**
98		* @dev Returns the downcasted uint16 from uint256, reverting on
99		* overflow (when the input is greater than largest uint16).
100		*
101		* Counterpart to Solidity's `uint16` operator.
102		*
103		* Requirements:
104		*
105		* - input must fit into 16 bits
106		*/
107		function toUint16(uint256 value) internal pure returns (uint16) {
108		require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
109		return uint16(value);
110		}
111
112		/**
113		* @dev Returns the downcasted uint8 from uint256, reverting on
114		* overflow (when the input is greater than largest uint8).
115		*
116		* Counterpart to Solidity's `uint8` operator.
117		*
118		* Requirements:
119		*
120		* - input must fit into 8 bits.
121		*/
122		function toUint8(uint256 value) internal pure returns (uint8) {
123		require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
124		return uint8(value);
125		}
126
127		/**
128		* @dev Converts a signed int256 into an unsigned uint256.
129		*
130		* Requirements:
131		*
132		* - input must be greater than or equal to 0.
133		*/
134	2×	function toUint256(int256 value) internal pure returns (uint256) {
135	6×	require(value >= 0, "SafeCast: value must be positive");
136		return uint256(value);
137		}
138
139		/**
140		* @dev Returns the downcasted int128 from int256, reverting on
141		* overflow (when the input is less than smallest int128 or
142		* greater than largest int128).
143		*
144		* Counterpart to Solidity's `int128` operator.
145		*
146		* Requirements:
147		*
148		* - input must fit into 128 bits
149		*
150		* _Available since v3.1._
151		*/
152		function toInt128(int256 value) internal pure returns (int128) {
153		require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
154		return int128(value);
155		}
156
157		/**
158		* @dev Returns the downcasted int64 from int256, reverting on
159		* overflow (when the input is less than smallest int64 or
160		* greater than largest int64).
161		*
162		* Counterpart to Solidity's `int64` operator.
163		*
164		* Requirements:
165		*
166		* - input must fit into 64 bits
167		*
168		* _Available since v3.1._
169		*/
170		function toInt64(int256 value) internal pure returns (int64) {
171		require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
172		return int64(value);
173		}
174
175		/**
176		* @dev Returns the downcasted int32 from int256, reverting on
177		* overflow (when the input is less than smallest int32 or
178		* greater than largest int32).
179		*
180		* Counterpart to Solidity's `int32` operator.
181		*
182		* Requirements:
183		*
184		* - input must fit into 32 bits
185		*
186		* _Available since v3.1._
187		*/
188		function toInt32(int256 value) internal pure returns (int32) {
189		require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
190		return int32(value);
191		}
192
193		/**
194		* @dev Returns the downcasted int16 from int256, reverting on
195		* overflow (when the input is less than smallest int16 or
196		* greater than largest int16).
197		*
198		* Counterpart to Solidity's `int16` operator.
199		*
200		* Requirements:
201		*
202		* - input must fit into 16 bits
203		*
204		* _Available since v3.1._
205		*/
206		function toInt16(int256 value) internal pure returns (int16) {
207		require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
208		return int16(value);
209		}
210
211		/**
212		* @dev Returns the downcasted int8 from int256, reverting on
213		* overflow (when the input is less than smallest int8 or
214		* greater than largest int8).
215		*
216		* Counterpart to Solidity's `int8` operator.
217		*
218		* Requirements:
219		*
220		* - input must fit into 8 bits.
221		*
222		* _Available since v3.1._
223		*/
224		function toInt8(int256 value) internal pure returns (int8) {
225		require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
226		return int8(value);
227		}
228
229		/**
230		* @dev Converts an unsigned uint256 into a signed int256.
231		*
232		* Requirements:
233		*
234		* - input must be less than or equal to maxInt256.
235		*/
236	6×	function toInt256(uint256 value) internal pure returns (int256) {
237		// Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
238	20×	require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
239	2×	return int256(value);
240		}
241		}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import {Properties} from "./Properties.sol";
5
6		// echidna test/recon/CryticTester.sol --contract CryticTester --config echidna.yaml
7	332×	contract CryticTester is Properties {}

1		// SPDX-License-Identifier: BUSL-1.1
2		pragma solidity ^0.8.0;
3
4		import {Echidna} from "../../contracts/contracts/echidna/Echidna.sol";
5
6		/// @notice scfuzzbench adaptation layer: canary checks on top of the
7		/// upstream OUSD Echidna suite. Assertion failures are surfaced the same
8		/// way for Echidna, Medusa, Foundry, and Recon (AssertionFailed event +
9		/// assert), and dedup to the emitting function name across fuzzers.
10		abstract contract Properties is Echidna {
11		string internal constant ASSERTION_CANARY = "!!! canary assertion";
12		string internal constant INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE = "Canary invariant";
13
14		event AssertionFailed(string reason);
15
16	1×	function t(bool b, string memory reason) internal {
17	3×	if (!b) {
18	17×	emit AssertionFailed(reason);
19	3×	assert(false);
20		}
21		}
22
23	6×	function invariant_canary() public returns (bool) {
24	20×	t(false, INVARIANT_CANARY_GLOBAL_INVARIANT_FAILURE);
25	0	return true;
26		}
27
28	11×	function assert_canary_ASSERTION_CANARY(uint256 entropy) public {
29	22×	t(entropy > 0, ASSERTION_CANARY);
30		}
31		}