feat: remove transfer restriction function from backing eigen (#1245)

**Motivation:**

per ELIP-5, remove transfer restriction function from backing eigen

**Modifications:**

remove transfer restriction function from backing eigen

**Result:**

remove transfer restriction function from backing eigen

Author: bowenli86

src/contracts/token/BackingEigen.sol

@@ -11,22 +11,19 @@ contract BackingEigen is OwnableUpgradeable, ERC20VotesUpgradeable {
     IERC20 public immutable EIGEN;
 
     /// STORAGE
+    /// @dev Do not remove, deprecated storage.
     /// @notice the timestamp after which transfer restrictions are disabled
-    uint256 public transferRestrictionsDisabledAfter;
+    uint256 internal __dreprecated_transferRestrictionsDisabledAfter;
+    /// @dev Do not remove, deprecated storage.
     /// @notice mapping of addresses that are allowed to transfer tokens to any address
-    mapping(address => bool) public allowedFrom;
+    mapping(address => bool) internal __dreprecated_allowedFrom;
+    /// @dev Do not remove, deprecated storage.
     /// @notice mapping of addresses that are allowed to receive tokens from any address
-    mapping(address => bool) public allowedTo;
+    mapping(address => bool) internal __dreprecated_allowedTo;
+
     // @notice whether or not an address is allowed to mint new bEIGEN tokens
     mapping(address => bool) public isMinter;
 
-    /// @notice event emitted when the allowedFrom status of an address is set
-    event SetAllowedFrom(address indexed from, bool isAllowedFrom);
-    /// @notice event emitted when the allowedTo status of an address is set
-    event SetAllowedTo(address indexed to, bool isAllowedTo);
-    /// @notice event emitted when the transfer restrictions are disabled
-    event TransferRestrictionsDisabled();
-    /// @notice event emitted when the EIGEN token is backed
     event Backed();
     // @notice event emitted when the `isMinter` mapping is modified
     event IsMinterModified(address indexed minterAddress, bool newStatus);
@@ -75,52 +72,12 @@ contract BackingEigen is OwnableUpgradeable, ERC20VotesUpgradeable {
         _transferOwnership(initialOwner);
         __ERC20Permit_init("bEIGEN");
 
-        // set transfer restrictions to be disabled at type(uint256).max to be set down later
-        transferRestrictionsDisabledAfter = type(uint256).max;
-
-        // the EIGEN contract should be allowed to transfer tokens to any address for unwrapping
-        // likewise, anyone should be able to transfer bEIGEN to EIGEN for wrapping
-        _setAllowedFrom(address(EIGEN), true);
-        _setAllowedTo(address(EIGEN), true);
-
         // Mint the entire supply of EIGEN - this is a one-time event that
         // ensures bEIGEN fully backs EIGEN.
         _mint(address(EIGEN), 1_673_646_668_284_660_000_000_000_000);
         emit Backed();
     }
 
-    /// EXTERNAL FUNCTIONS
-
-    /**
-     * @notice This function allows the owner to set the allowedFrom status of an address
-     * @param from the address whose allowedFrom status is being set
-     * @param isAllowedFrom the new allowedFrom status
-     */
-    function setAllowedFrom(address from, bool isAllowedFrom) external onlyOwner {
-        _setAllowedFrom(from, isAllowedFrom);
-    }
-
-    /**
-     * @notice This function allows the owner to set the allowedTo status of an address
-     * @param to the address whose allowedTo status is being set
-     * @param isAllowedTo the new allowedTo status
-     */
-    function setAllowedTo(address to, bool isAllowedTo) external onlyOwner {
-        _setAllowedTo(to, isAllowedTo);
-    }
-
-    /**
-     * @notice Allows the owner to disable transfer restrictions
-     */
-    function disableTransferRestrictions() external onlyOwner {
-        require(
-            transferRestrictionsDisabledAfter == type(uint256).max,
-            "BackingEigen.disableTransferRestrictions: transfer restrictions are already disabled"
-        );
-        transferRestrictionsDisabledAfter = 0;
-        emit TransferRestrictionsDisabled();
-    }
-
     /// VIEW FUNCTIONS
 
     /**
@@ -139,34 +96,4 @@ contract BackingEigen is OwnableUpgradeable, ERC20VotesUpgradeable {
     function CLOCK_MODE() public pure override returns (string memory) {
         return "mode=timestamp";
     }
-
-    /// INTERNAL FUNCTIONS
-
-    function _setAllowedFrom(address from, bool isAllowedFrom) internal {
-        allowedFrom[from] = isAllowedFrom;
-        emit SetAllowedFrom(from, isAllowedFrom);
-    }
-
-    function _setAllowedTo(address to, bool isAllowedTo) internal {
-        allowedTo[to] = isAllowedTo;
-        emit SetAllowedTo(to, isAllowedTo);
-    }
-
-    /**
-     * @notice Overrides the beforeTokenTransfer function to enforce transfer restrictions
-     * @param from the address tokens are being transferred from
-     * @param to the address tokens are being transferred to
-     * @param amount the amount of tokens being transferred
-     */
-    function _beforeTokenTransfer(address from, address to, uint256 amount) internal override {
-        // if transfer restrictions are enabled
-        if (block.timestamp <= transferRestrictionsDisabledAfter) {
-            // if both from and to are not whitelisted
-            require(
-                allowedFrom[from] || allowedTo[to] || from == address(0),
-                "BackingEigen._beforeTokenTransfer: from or to must be whitelisted"
-            );
-        }
-        super._beforeTokenTransfer(from, to, amount);
-    }
 }

src/test/token/EigenWrapping.t.sol

@@ -26,14 +26,8 @@ contract EigenWrappingTests is Test {
     uint totalSupply = 1.67e9 ether;
 
     // EVENTS FROM EIGEN.sol
-    /// @notice event emitted when the allowedFrom status of an address is set
-    event SetAllowedFrom(address indexed from, bool isAllowedFrom);
-    /// @notice event emitted when the allowedTo status of an address is set
-    event SetAllowedTo(address indexed to, bool isAllowedTo);
     /// @notice event emitted when a minter mints
     event Mint(address indexed minter, uint amount);
-    /// @notice event emitted when the transfer restrictions are disabled
-    event TransferRestrictionsDisabled();
 
     modifier filterAddress(address fuzzedAddress) {
         vm.assume(!fuzzedOutAddresses[fuzzedAddress]);
@@ -70,7 +64,9 @@ contract EigenWrappingTests is Test {
         vm.assume(unwrapper != address(0));
 
         _simulateMint();
-        _simulateBackingAndSetTransferRestrictions();
+
+        // initialize bEIGEN
+        bEIGEN.initialize(minter1);
 
         // minter1 balance
         uint minter1Balance = eigen.balanceOf(minter1);
@@ -105,7 +101,9 @@ contract EigenWrappingTests is Test {
         vm.assume(wrapper != address(0));
 
         _simulateMint();
-        _simulateBackingAndSetTransferRestrictions();
+
+        // initialize bEIGEN
+        bEIGEN.initialize(minter1);
 
         // initial bEIGEN balance
         uint initialBEIGENBalanceOfEigenToken = bEIGEN.balanceOf(address(eigen));
@@ -142,7 +140,9 @@ contract EigenWrappingTests is Test {
 
     function test_CannotUnwrapMoreThanBalance(address unwrapper, uint unwrapAmount) public filterAddress(unwrapper) {
         _simulateMint();
-        _simulateBackingAndSetTransferRestrictions();
+
+        // initialize bEIGEN
+        bEIGEN.initialize(minter1);
 
         // unwrap amount should be less than minter1 balance
         unwrapAmount = unwrapAmount % eigen.balanceOf(minter1);
@@ -159,7 +159,9 @@ contract EigenWrappingTests is Test {
 
     function test_CannotWrapMoreThanBalance(address wrapper, uint wrapAmount) public filterAddress(wrapper) {
         _simulateMint();
-        _simulateBackingAndSetTransferRestrictions();
+
+        // initialize bEIGEN
+        bEIGEN.initialize(minter1);
 
         // wrap amount should be less than minter1 balance
         wrapAmount = wrapAmount % eigen.balanceOf(minter1);
@@ -185,12 +187,4 @@ contract EigenWrappingTests is Test {
         EigenHarness(address(eigen)).mint(minter1, totalSupply / 2);
         EigenHarness(address(eigen)).mint(minter2, totalSupply / 2);
     }
-
-    function _simulateBackingAndSetTransferRestrictions() internal {
-        bEIGEN.initialize(minter1);
-
-        vm.startPrank(minter1);
-        bEIGEN.setAllowedFrom(minter1, true);
-        vm.stopPrank();
-    }
 }

src/test/token/bEIGEN.t.sol

@@ -48,8 +48,6 @@ contract bEIGENTest is Test {
 
         // check that the owner is initialOwner
         assertEq(bEIGEN.owner(), initialOwner);
-        // check the transfer restrictions are disabled after one year in the future
-        assertEq(bEIGEN.transferRestrictionsDisabledAfter(), type(uint).max);
     }
 
     function testFuzz_CanBackTheEigenToken(uint eigenSupply) public {
@@ -89,8 +87,6 @@ contract bEIGENTest is Test {
 
     function test_burn() public {
         test_setIsMinterAndMint();
-        vm.prank(initialOwner);
-        bEIGEN.setAllowedFrom(mintTo, true);
 
         uint amountToBurn = 1005e18;
         uint balanceBefore = bEIGEN.balanceOf(mintTo);