Fund the withdrawal queue when WETH is swapped into the ARM

src/contracts/AbstractARM.sol

@@ -159,4 +159,9 @@ abstract contract AbstractARM is OwnableOperable {
     function _transferAsset(address asset, address to, uint256 amount) internal virtual {
         IERC20(asset).transfer(to, amount);
     }
+
+    /// @dev Hook to transfer assets into the ARM contract
+    function _transferAssetFrom(address asset, address from, address to, uint256 amount) internal virtual {
+        IERC20(asset).transferFrom(from, to, amount);
+    }
 }

src/contracts/FixedPriceARM.sol

@@ -54,7 +54,7 @@ abstract contract FixedPriceARM is AbstractARM {
         amountOut = amountIn * price / PRICE_SCALE;
 
         // Transfer the input tokens from the caller to this ARM contract
-        inToken.transferFrom(msg.sender, address(this), amountIn);
+        _transferAssetFrom(address(inToken), msg.sender, address(this), amountIn);
 
         // Transfer the output tokens to the recipient
         _transferAsset(address(outToken), to, amountOut);
@@ -78,7 +78,7 @@ abstract contract FixedPriceARM is AbstractARM {
         amountIn = ((amountOut * PRICE_SCALE) / price) + 1; // +1 to always round in our favor
 
         // Transfer the input tokens from the caller to this ARM contract
-        inToken.transferFrom(msg.sender, address(this), amountIn);
+        _transferAssetFrom(address(inToken), msg.sender, address(this), amountIn);
 
         // Transfer the output tokens to the recipient
         _transferAsset(address(outToken), to, amountOut);

src/contracts/LidoFixedPriceMultiLpARM.sol

@@ -71,6 +71,14 @@ contract LidoFixedPriceMultiLpARM is
         MultiLP._transferAsset(asset, to, transferAmount);
     }
 
+    /// @dev Funds the ARM's withdrawal queue when swaps send WETH to the ARM
+    function _transferAssetFrom(address asset, address from, address to, uint256 amount)
+        internal
+        override(AbstractARM, MultiLP)
+    {
+        MultiLP._transferAssetFrom(asset, from, to, amount);
+    }
+
     function _externalWithdrawQueue() internal view override(MultiLP, LidoLiquidityManager) returns (uint256) {
         return LidoLiquidityManager._externalWithdrawQueue();
     }

src/contracts/MultiLP.sol

@@ -240,11 +240,20 @@ abstract contract MultiLP is AbstractARM, ERC20Upgradeable {
     /// @dev Ensure any liquidity assets reserved for the withdrawal queue are not used
     /// in swaps that send liquidity assets out of the ARM
     function _transferAsset(address asset, address to, uint256 amount) internal virtual override {
-        require(asset == liquidityAsset && amount <= _liquidityAvailable(), "ARM: Insufficient liquidity");
+        if (asset == liquidityAsset) {
+            require(amount <= _liquidityAvailable(), "ARM: Insufficient liquidity");
+        }
 
         IERC20(asset).transfer(to, amount);
     }
 
+    /// @dev Funds the ARM's withdrawal queue when swaps send liquidity assets to the ARM
+    function _transferAssetFrom(address asset, address from, address to, uint256 amount) internal virtual override {
+        IERC20(asset).transferFrom(from, to, amount);
+
+        _addWithdrawalQueueLiquidity();
+    }
+
     /// @notice The total amount of assets in the ARM and external withdrawal queue,
     /// less the liquidity assets reserved for the withdrawal queue
     function totalAssets() public view virtual returns (uint256 assets) {

test/fork/LidoFixedPriceMultiLpARM/SwapExactTokensForTokens.t.sol

@@ -116,7 +116,7 @@ contract Fork_Concrete_LidoFixedPriceMultiLpARM_SwapExactTokensForTokens_Test is
 
         initialBalance = weth.balanceOf(address(lidoFixedPriceMulltiLpARM));
         deal(address(steth), address(this), initialBalance * 2);
-        vm.expectRevert(); // Lido error
+        vm.expectRevert("ARM: Insufficient liquidity");
         lidoFixedPriceMulltiLpARM.swapExactTokensForTokens(
             steth, // inToken
             weth, // outToken