can do without OZ v5

Author: d10r

packages/ethereum-contracts/contracts/interfaces/superfluid/ISuperToken.sol

@@ -3,7 +3,7 @@ pragma solidity >= 0.8.11;
 
 import { ISuperfluidToken } from "./ISuperfluidToken.sol";
 import { IERC20, IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
-import { IERC20Permit } from "@openzeppelin/contracts-v5/token/ERC20/extensions/IERC20Permit.sol";
+import { IERC20Permit } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol";
 import { IERC777 } from "@openzeppelin/contracts/token/ERC777/IERC777.sol";
 import { IPoolAdminNFT } from "../agreements/gdav1/IPoolAdminNFT.sol";
 import { IPoolMemberNFT } from "../agreements/gdav1/IPoolMemberNFT.sol";

packages/ethereum-contracts/contracts/superfluid/SuperToken.sol

@@ -20,9 +20,7 @@ import { SafeCast } from "@openzeppelin/contracts/utils/math/SafeCast.sol";
 import { IERC777Recipient } from "@openzeppelin/contracts/token/ERC777/IERC777Recipient.sol";
 import { IERC777Sender } from "@openzeppelin/contracts/token/ERC777/IERC777Sender.sol";
 import { Address } from "@openzeppelin/contracts/utils/Address.sol";
-
-import { ECDSA } from "@openzeppelin/contracts-v5/utils/cryptography/ECDSA.sol";
-import { MessageHashUtils } from "@openzeppelin/contracts-v5/utils/cryptography/MessageHashUtils.sol";
+import { ECDSA } from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
 
 // placeholder types needed as an intermediate step before complete removal of FlowNFTs
 // solhint-disable-next-line no-empty-blocks
@@ -259,7 +257,18 @@ contract SuperToken is
             )
         );
 
-        bytes32 hash = MessageHashUtils.toTypedDataHash(DOMAIN_SEPARATOR(), structHash);
+        bytes32 domainSeparator = DOMAIN_SEPARATOR();
+        // Get the keccak256 digest of the EIP-712 typed data (ERC-191 version `0x01`).
+        // solhint-disable-next-line max-line-length
+        // Snippet taken from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v5.2.0/contracts/utils/cryptography/MessageHashUtils.sol
+        bytes32 hash;
+        assembly ("memory-safe") {
+            let ptr := mload(0x40)
+            mstore(ptr, hex"19_01")
+            mstore(add(ptr, 0x02), domainSeparator)
+            mstore(add(ptr, 0x22), structHash)
+            hash := keccak256(ptr, 0x42)
+        }
 
         address signer = ECDSA.recover(hash, v, r, s);
         if (signer != owner) revert SUPER_TOKEN_PERMIT_INVALID_SIGNER(signer, owner);

packages/ethereum-contracts/package.json

@@ -6,7 +6,6 @@
         "@decentral.ee/web3-helpers": "0.5.3",
         "@nomiclabs/hardhat-ethers": "2.2.3",
         "@openzeppelin/contracts": "4.9.6",
-        "@openzeppelin/contracts-v5": "npm:@openzeppelin/contracts@5.2.0",
         "@truffle/contract": "4.6.31",
         "ethereumjs-tx": "2.1.2",
         "ethereumjs-util": "7.1.5",

yarn.lock

@@ -3318,11 +3318,6 @@
     find-up "^4.1.0"
     fs-extra "^8.1.0"
 
-"@openzeppelin/contracts-v5@npm:@openzeppelin/contracts@5.2.0":
-  version "5.2.0"
-  resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-5.2.0.tgz#bd020694218202b811b0ea3eec07277814c658da"
-  integrity sha512-bxjNie5z89W1Ea0NZLZluFh8PrFNn9DH8DQlujEok2yjsOlraUPKID5p1Wk3qdNbf6XkQ1Os2RvfiHrrXLHWKA==
-
 "@openzeppelin/contracts@4.9.6", "@openzeppelin/contracts@^4.9.6":
   version "4.9.6"
   resolved "https://registry.yarnpkg.com/@openzeppelin/contracts/-/contracts-4.9.6.tgz#2a880a24eb19b4f8b25adc2a5095f2aa27f39677"