feat: mintable with permit

packages/contracts-bedrock/semver-lock.json

@@ -208,12 +208,12 @@
     "sourceCodeHash": "0x3a0a294932d6deba043f6a2b46b4e8477ee96e7fb054d7e7229a43ce4352c68d"
   },
   "src/universal/OptimismMintableERC20.sol": {
-    "initCodeHash": "0xfc77e4db406c232d8b84a3f77b939fb08fa27852faa5f4b0d78d998402caf308",
-    "sourceCodeHash": "0xd7957c662ef03fc0cc3440a6ec6737a55f90b52a977262a260cd99fe96494267"
+    "initCodeHash": "0x28c88484e1932253d6d12954492ac8a70744dc15c84429089af9944e5b158fd9",
+    "sourceCodeHash": "0x740b4043436d1b314ee3ba145acfcde60b6abd8416ea594f2b8e890b5d0bce6b"
   },
   "src/universal/OptimismMintableERC20Factory.sol": {
-    "initCodeHash": "0x1cc94179ce28fb34c8e28b8d2015b95588e93a45730dae9ee7da859a9f66e0e6",
-    "sourceCodeHash": "0x46d1d4a9ed1b1f4c60d42bf6c9982ffc72cbd759a4aae5246f89ccbb8699c2a1"
+    "initCodeHash": "0x3ebd2297c0af2856a432daf29d186d0751f7edb1c777abbe136953038cf5d1ba",
+    "sourceCodeHash": "0xf8425f65eb5520d55710907d67a9d6fa277263285e1b79ba299815d1c76919a3"
   },
   "src/universal/OptimismMintableERC721.sol": {
     "initCodeHash": "0x5a995fc043f8268a6d5c6284ad85b0de21328cd47277114aeba2c03484deaf91",

packages/contracts-bedrock/snapshots/abi/OptimismMintableERC20.json

@@ -43,6 +43,32 @@
     "stateMutability": "view",
     "type": "function"
   },
+  {
+    "inputs": [],
+    "name": "DOMAIN_SEPARATOR",
+    "outputs": [
+      {
+        "internalType": "bytes32",
+        "name": "",
+        "type": "bytes32"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "PERMIT2",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "pure",
+    "type": "function"
+  },
   {
     "inputs": [],
     "name": "REMOTE_TOKEN",
@@ -60,12 +86,12 @@
     "inputs": [
       {
         "internalType": "address",
-        "name": "owner",
+        "name": "_owner",
         "type": "address"
       },
       {
         "internalType": "address",
-        "name": "spender",
+        "name": "_spender",
         "type": "address"
       }
     ],
@@ -272,6 +298,68 @@
     "stateMutability": "view",
     "type": "function"
   },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "owner",
+        "type": "address"
+      }
+    ],
+    "name": "nonces",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "owner",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "spender",
+        "type": "address"
+      },
+      {
+        "internalType": "uint256",
+        "name": "value",
+        "type": "uint256"
+      },
+      {
+        "internalType": "uint256",
+        "name": "deadline",
+        "type": "uint256"
+      },
+      {
+        "internalType": "uint8",
+        "name": "v",
+        "type": "uint8"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "r",
+        "type": "bytes32"
+      },
+      {
+        "internalType": "bytes32",
+        "name": "s",
+        "type": "bytes32"
+      }
+    ],
+    "name": "permit",
+    "outputs": [],
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
   {
     "inputs": [],
     "name": "remoteToken",

packages/contracts-bedrock/snapshots/storageLayout/OptimismMintableERC20.json

@@ -33,5 +33,19 @@
     "offset": 0,
     "slot": "4",
     "type": "string"
+  },
+  {
+    "bytes": "32",
+    "label": "_nonces",
+    "offset": 0,
+    "slot": "5",
+    "type": "mapping(address => struct Counters.Counter)"
+  },
+  {
+    "bytes": "32",
+    "label": "_PERMIT_TYPEHASH_DEPRECATED_SLOT",
+    "offset": 0,
+    "slot": "6",
+    "type": "bytes32"
   }
 ]

packages/contracts-bedrock/src/universal/OptimismMintableERC20.sol

@@ -2,17 +2,19 @@
 pragma solidity 0.8.15;
 
 import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import { ERC20Permit } from "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol";
 import { IERC165 } from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
 import { ILegacyMintableERC20, IOptimismMintableERC20 } from "src/universal/interfaces/IOptimismMintableERC20.sol";
 import { ISemver } from "src/universal/interfaces/ISemver.sol";
+import { Preinstalls } from "src/libraries/Preinstalls.sol";
 
 /// @title OptimismMintableERC20
 /// @notice OptimismMintableERC20 is a standard extension of the base ERC20 token contract designed
 ///         to allow the StandardBridge contracts to mint and burn tokens. This makes it possible to
 ///         use an OptimismMintablERC20 as the L2 representation of an L1 token, or vice-versa.
 ///         Designed to be backwards compatible with the older StandardL2ERC20 token which was only
 ///         meant for use on L2.
-contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20, ERC20, ISemver {
+contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20, ERC20Permit, ISemver {
     /// @notice Address of the corresponding version of this token on the remote chain.
     address public immutable REMOTE_TOKEN;
 
@@ -39,8 +41,16 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
     }
 
     /// @notice Semantic version.
-    /// @custom:semver 1.3.1-beta.1
-    string public constant version = "1.3.1-beta.1";
+    /// @custom:semver 1.4.0-beta.1
+    string public constant version = "1.4.0-beta.1";
+
+    /// @notice Getter function for the permit2 address. It deterministically deployed
+    ///         so it will always be at the same address. It is also included as a preinstall,
+    ///         so it exists in the genesis state of chains.
+    /// @return Address of permit2 on this network.
+    function PERMIT2() public pure returns (address) {
+        return Preinstalls.Permit2;
+    }
 
     /// @param _bridge      Address of the L2 standard bridge.
     /// @param _remoteToken Address of the corresponding L1 token.
@@ -54,12 +64,35 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
         uint8 _decimals
     )
         ERC20(_name, _symbol)
+        ERC20Permit(_name)
     {
         REMOTE_TOKEN = _remoteToken;
         BRIDGE = _bridge;
         DECIMALS = _decimals;
     }
 
+    /// @dev Returns the number of decimals used to get its user representation.
+    /// For example, if `decimals` equals `2`, a balance of `505` tokens should
+    /// be displayed to a user as `5.05` (`505 / 10 ** 2`).
+    /// NOTE: This information is only used for _display_ purposes: it in
+    /// no way affects any of the arithmetic of the contract, including
+    /// {IERC20-balanceOf} and {IERC20-transfer}.
+    function decimals() public view override returns (uint8) {
+        return DECIMALS;
+    }
+
+    /// @notice Returns the allowance for a spender on the owner's tokens.
+    ///         If the spender is the permit2 address, returns the maximum uint256 value.
+    /// @param _owner   owner of the tokens.
+    /// @param _spender spender of the tokens.
+    /// @return Allowance for the spender.
+    function allowance(address _owner, address _spender) public view override returns (uint256) {
+        if (_spender == PERMIT2()) {
+            return type(uint256).max;
+        }
+        return super.allowance(_owner, _spender);
+    }
+
     /// @notice Allows the StandardBridge on this network to mint tokens.
     /// @param _to     Address to mint tokens to.
     /// @param _amount Amount of tokens to mint.
@@ -127,14 +160,4 @@ contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20,
     function bridge() public view returns (address) {
         return BRIDGE;
     }
-
-    /// @dev Returns the number of decimals used to get its user representation.
-    /// For example, if `decimals` equals `2`, a balance of `505` tokens should
-    /// be displayed to a user as `5.05` (`505 / 10 ** 2`).
-    /// NOTE: This information is only used for _display_ purposes: it in
-    /// no way affects any of the arithmetic of the contract, including
-    /// {IERC20-balanceOf} and {IERC20-transfer}.
-    function decimals() public view override returns (uint8) {
-        return DECIMALS;
-    }
 }

packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol

@@ -49,7 +49,7 @@ contract OptimismMintableERC20Factory is ISemver, Initializable, IOptimismERC20F
     ///         is responsible for deploying OptimismMintableERC20 contracts.
     /// @notice Semantic version.
     /// @custom:semver 1.10.1-beta.1
-    string public constant version = "1.10.1-beta.1";
+    string public constant version = "1.10.1-beta.2";
 
     /// @notice Constructs the OptimismMintableERC20Factory contract.
     constructor() {

packages/contracts-bedrock/test/universal/OptimismMintableERC20.t.sol

@@ -46,6 +46,20 @@ contract OptimismMintableERC20_Test is Bridge_Initializer {
         assertEq(L2Token.balanceOf(alice), 100);
     }
 
+    function test_allowance_permit2_max() external view {
+        assertEq(L2Token.allowance(alice, L2Token.PERMIT2()), type(uint256).max);
+    }
+
+    function test_permit2_transferFrom() external {
+        vm.prank(address(l2StandardBridge));
+        L2Token.mint(alice, 100);
+
+        assertEq(L2Token.balanceOf(bob), 0);
+        vm.prank(L2Token.PERMIT2());
+        L2Token.transferFrom(alice, bob, 100);
+        assertEq(L2Token.balanceOf(bob), 100);
+    }
+
     function test_mint_notBridge_reverts() external {
         // NOT the bridge
         vm.expectRevert("OptimismMintableERC20: only bridge can mint and burn");