Various small improvements

src/Morpho.sol

@@ -78,6 +78,7 @@ contract Morpho is IMorpho {
     /// @notice Initializes the contract.
     /// @param newOwner The new owner of the contract.
     constructor(address newOwner) {
+        require(newOwner != address(0), ErrorsLib.ZERO_ADDRESS);
         owner = newOwner;
 
         DOMAIN_SEPARATOR = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256("Morpho"), block.chainid, address(this)));
@@ -405,6 +406,7 @@ contract Morpho is IMorpho {
     /// @inheritdoc IMorpho
     /// @dev Warning: reverts if the signature has already been submitted.
     /// @dev The signature is malleable, but it has no impact on the security here.
+    /// @dev The nonce is passed as argument to be able to revert with a different error message.
     function setAuthorizationWithSig(Authorization memory authorization, Signature calldata signature) external {
         require(block.timestamp < authorization.deadline, ErrorsLib.SIGNATURE_EXPIRED);
         require(authorization.nonce == nonce[authorization.authorizer]++, ErrorsLib.INVALID_NONCE);

src/interfaces/IMorpho.sol

@@ -53,10 +53,13 @@ interface IMorpho {
     function DOMAIN_SEPARATOR() external view returns (bytes32);
 
     /// @notice The owner of the contract.
+    /// @dev It has the power to change the owner.
+    /// @dev It has the power to set fees on markets and set the fee recipient.
+    /// @dev It has the power to enable but not disable IRMs and LLTVs.
     function owner() external view returns (address);
 
-    /// @notice The fee recipient.
-    /// @dev The recipient receives the fees through a supply position.
+    /// @notice The fee recipient of all markets.
+    /// @dev The recipient receives the fees of a given market through a supply position on this market.
     function feeRecipient() external view returns (address);
 
     /// @notice Users' storage for market `id`.
@@ -75,8 +78,8 @@ interface IMorpho {
     /// @dev Anyone is authorized to modify their own positions, regardless of this variable.
     function isAuthorized(address authorizer, address authorized) external view returns (bool);
 
-    /// @notice The `user`'s current nonce. Used to prevent replay attacks with EIP-712 signatures.
-    function nonce(address user) external view returns (uint256);
+    /// @notice The `authorizer`'s current nonce. Used to prevent replay attacks with EIP-712 signatures.
+    function nonce(address authorizer) external view returns (uint256);
 
     /// @notice The market params corresponding to `id`.
     function idToMarketParams(Id id)

src/libraries/MathLib.sol

@@ -13,11 +13,6 @@ library MathLib {
         return mulDivDown(x, y, WAD);
     }
 
-    /// @dev (x * y) / WAD rounded up.
-    function wMulUp(uint256 x, uint256 y) internal pure returns (uint256) {
-        return mulDivUp(x, y, WAD);
-    }
-
     /// @dev (x * WAD) / y rounded down.
     function wDivDown(uint256 x, uint256 y) internal pure returns (uint256) {
         return mulDivDown(x, WAD, y);

test/forge/integration/TestIntegrationOnlyOwner.t.sol

@@ -8,6 +8,11 @@ contract IntegrationOnlyOwnerTest is BaseTest {
     using MathLib for uint256;
     using MorphoLib for Morpho;
 
+    function testDeployWithAddressZero() public {
+        vm.expectRevert();
+        new Morpho(address(0));
+    }
+
     function testSetOwnerWhenNotOwner(address addressFuzz) public {
         vm.assume(addressFuzz != OWNER);