little readability improvement + unchecked on loops

.forge-snapshots/lockdown.snap

@@ -1 +1 @@
-28435
+28447

.forge-snapshots/permitBatchCleanWrite.snap

@@ -1 +1 @@
-91924
+91826

.forge-snapshots/permitBatchDirtyWrite.snap

@@ -1 +1 @@
-57724
+57626

.forge-snapshots/permitBatchTransferFromMultipleTokens.snap

@@ -1 +1 @@
-143387
+143240

.forge-snapshots/permitBatchTransferFromSingleToken.snap

@@ -1 +1 @@
-88867
+88818

.forge-snapshots/permitTransferFromBatchTypedWitness.snap

@@ -1 +1 @@
-120325
+120227

.forge-snapshots/single recipient 2 tokens.snap

@@ -1 +1 @@
-118525
+118427

.forge-snapshots/single recipient many tokens.snap

@@ -1 +1 @@
-133544
+133054

.gas-snapshot

@@ -1,26 +1,26 @@
-AllowanceTransferInvariants:invariant_balanceEqualsSpent() (runs: 256, calls: 3840, reverts: 886)
-AllowanceTransferInvariants:invariant_permit2NeverHoldsBalance() (runs: 256, calls: 3840, reverts: 886)
-AllowanceTransferInvariants:invariant_spendNeverExceedsPermit() (runs: 256, calls: 3840, reverts: 886)
+AllowanceTransferInvariants:invariant_balanceEqualsSpent() (runs: 256, calls: 3840, reverts: 885)
+AllowanceTransferInvariants:invariant_permit2NeverHoldsBalance() (runs: 256, calls: 3840, reverts: 885)
+AllowanceTransferInvariants:invariant_spendNeverExceedsPermit() (runs: 256, calls: 3840, reverts: 885)
 AllowanceTransferTest:testApprove() (gas: 47561)
 AllowanceTransferTest:testBatchTransferFrom() (gas: 159268)
 AllowanceTransferTest:testBatchTransferFromDifferentOwners() (gas: 235508)
-AllowanceTransferTest:testBatchTransferFromMultiToken() (gas: 231810)
+AllowanceTransferTest:testBatchTransferFromMultiToken() (gas: 231712)
 AllowanceTransferTest:testBatchTransferFromWithGasSnapshot() (gas: 159818)
 AllowanceTransferTest:testExcessiveInvalidation() (gas: 64136)
 AllowanceTransferTest:testInvalidateMultipleNonces() (gas: 83139)
 AllowanceTransferTest:testInvalidateNonces() (gas: 62679)
 AllowanceTransferTest:testInvalidateNoncesInvalid() (gas: 16261)
-AllowanceTransferTest:testLockdown() (gas: 145952)
-AllowanceTransferTest:testLockdownEvent() (gas: 117758)
+AllowanceTransferTest:testLockdown() (gas: 145866)
+AllowanceTransferTest:testLockdownEvent() (gas: 117672)
 AllowanceTransferTest:testMaxAllowance() (gas: 134993)
 AllowanceTransferTest:testMaxAllowanceDirtyWrite() (gas: 117582)
 AllowanceTransferTest:testPartialAllowance() (gas: 105067)
 AllowanceTransferTest:testReuseOrderedNonceInvalid() (gas: 69095)
 AllowanceTransferTest:testSetAllowance() (gas: 89583)
-AllowanceTransferTest:testSetAllowanceBatch() (gas: 133608)
-AllowanceTransferTest:testSetAllowanceBatchDifferentNonces() (gas: 118583)
-AllowanceTransferTest:testSetAllowanceBatchDirtyWrite() (gas: 99144)
-AllowanceTransferTest:testSetAllowanceBatchEvent() (gas: 115892)
+AllowanceTransferTest:testSetAllowanceBatch() (gas: 133510)
+AllowanceTransferTest:testSetAllowanceBatchDifferentNonces() (gas: 118485)
+AllowanceTransferTest:testSetAllowanceBatchDirtyWrite() (gas: 99046)
+AllowanceTransferTest:testSetAllowanceBatchEvent() (gas: 115794)
 AllowanceTransferTest:testSetAllowanceCompactSig() (gas: 89543)
 AllowanceTransferTest:testSetAllowanceDeadlinePassed() (gas: 56500)
 AllowanceTransferTest:testSetAllowanceDirtyWrite() (gas: 72175)
@@ -72,20 +72,20 @@ Permit2LibTest:testTransferFrom2Full() (gas: 53258)
 Permit2LibTest:testTransferFrom2InvalidAmount() (gas: 12710)
 Permit2LibTest:testTransferFrom2NonPermitToken() (gas: 53104)
 SignatureTransferTest:testCorrectWitnessTypehashes() (gas: 3075)
-SignatureTransferTest:testGasMultiplePermitBatchTransferFrom() (gas: 270919)
-SignatureTransferTest:testGasSinglePermitBatchTransferFrom() (gas: 186316)
+SignatureTransferTest:testGasMultiplePermitBatchTransferFrom() (gas: 270772)
+SignatureTransferTest:testGasSinglePermitBatchTransferFrom() (gas: 186267)
 SignatureTransferTest:testGasSinglePermitTransferFrom() (gas: 123850)
 SignatureTransferTest:testInvalidateUnorderedNonces() (gas: 41268)
-SignatureTransferTest:testPermitBatchMultiPermitSingleTransfer() (gas: 133644)
-SignatureTransferTest:testPermitBatchTransferFrom() (gas: 162010)
-SignatureTransferTest:testPermitBatchTransferFromSingleRecipient() (gas: 190319)
-SignatureTransferTest:testPermitBatchTransferFromTypedWitness() (gas: 239854)
-SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidType() (gas: 84467)
-SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidTypeHash() (gas: 85864)
-SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidWitness() (gas: 85688)
-SignatureTransferTest:testPermitBatchTransferInvalidAmountsLengthMismatch() (gas: 43967)
-SignatureTransferTest:testPermitBatchTransferMultiAddr() (gas: 160406)
-SignatureTransferTest:testPermitBatchTransferSingleRecipientManyTokens() (gas: 211834)
+SignatureTransferTest:testPermitBatchMultiPermitSingleTransfer() (gas: 133546)
+SignatureTransferTest:testPermitBatchTransferFrom() (gas: 161912)
+SignatureTransferTest:testPermitBatchTransferFromSingleRecipient() (gas: 190221)
+SignatureTransferTest:testPermitBatchTransferFromTypedWitness() (gas: 239756)
+SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidType() (gas: 84369)
+SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidTypeHash() (gas: 85766)
+SignatureTransferTest:testPermitBatchTransferFromTypedWitnessInvalidWitness() (gas: 85590)
+SignatureTransferTest:testPermitBatchTransferInvalidAmountsLengthMismatch() (gas: 43869)
+SignatureTransferTest:testPermitBatchTransferMultiAddr() (gas: 160308)
+SignatureTransferTest:testPermitBatchTransferSingleRecipientManyTokens() (gas: 211344)
 SignatureTransferTest:testPermitTransferFrom() (gas: 93012)
 SignatureTransferTest:testPermitTransferFromCompactSig() (gas: 123927)
 SignatureTransferTest:testPermitTransferFromIncorrectSigLength() (gas: 51327)
@@ -96,14 +96,14 @@ SignatureTransferTest:testPermitTransferFromTypedWitness() (gas: 125271)
 SignatureTransferTest:testPermitTransferFromTypedWitnessInvalidType() (gas: 55906)
 SignatureTransferTest:testPermitTransferFromTypedWitnessInvalidTypehash() (gas: 56794)
 SignatureTransferTest:testPermitTransferSpendLessThanFull(uint256,uint128) (runs: 256, μ: 97989, ~: 99707)
-TypehashGeneration:testPermitBatch() (gas: 40493)
-TypehashGeneration:testPermitBatchTransferFrom() (gas: 49854)
-TypehashGeneration:testPermitBatchTransferFromWithWitness() (gas: 56587)
-TypehashGeneration:testPermitBatchTransferFromWithWitnessIncorrectPermitData() (gas: 56744)
-TypehashGeneration:testPermitBatchTransferFromWithWitnessIncorrectTypehashStub() (gas: 57229)
+TypehashGeneration:testPermitBatch() (gas: 40400)
+TypehashGeneration:testPermitBatchTransferFrom() (gas: 49756)
+TypehashGeneration:testPermitBatchTransferFromWithWitness() (gas: 56489)
+TypehashGeneration:testPermitBatchTransferFromWithWitnessIncorrectPermitData() (gas: 56646)
+TypehashGeneration:testPermitBatchTransferFromWithWitnessIncorrectTypehashStub() (gas: 57131)
 TypehashGeneration:testPermitSingle() (gas: 28117)
 TypehashGeneration:testPermitTransferFrom() (gas: 36520)
 TypehashGeneration:testPermitTransferFromWithWitness() (gas: 43369)
 TypehashGeneration:testPermitTransferFromWithWitnessIncorrectPermitData() (gas: 43430)
 TypehashGeneration:testPermitTransferFromWithWitnessIncorrectTypehashStub() (gas: 43833)
-MockPermit2Lib:testPermit2Code(address):(bool) (runs: 256, μ: 3025, ~: 3016)
+MockPermit2Lib:testPermit2Code(address):(bool) (runs: 256, μ: 3035, ~: 3016)

src/AllowanceTransfer.sol

@@ -47,10 +47,12 @@ contract AllowanceTransfer is IAllowanceTransfer, EIP712 {
         signature.verify(_hashTypedData(permitBatch.hash()), owner);
 
         address spender = permitBatch.spender;
-        unchecked {
-            uint256 length = permitBatch.details.length;
-            for (uint256 i = 0; i < length; ++i) {
-                _updateApproval(permitBatch.details[i], owner, spender);
+
+        uint256 length = permitBatch.details.length;
+        for (uint256 i = 0; i < length;) {
+            _updateApproval(permitBatch.details[i], owner, spender);
+            unchecked {
+                ++i;
             }
         }
     }
@@ -62,11 +64,12 @@ contract AllowanceTransfer is IAllowanceTransfer, EIP712 {
 
     /// @inheritdoc IAllowanceTransfer
     function transferFrom(AllowanceTransferDetails[] calldata transferDetails) external {
-        unchecked {
-            uint256 length = transferDetails.length;
-            for (uint256 i = 0; i < length; ++i) {
-                AllowanceTransferDetails memory transferDetail = transferDetails[i];
-                _transfer(transferDetail.from, transferDetail.to, transferDetail.amount, transferDetail.token);
+        uint256 length = transferDetails.length;
+        for (uint256 i = 0; i < length;) {
+            AllowanceTransferDetails memory transferDetail = transferDetails[i];
+            _transfer(transferDetail.from, transferDetail.to, transferDetail.amount, transferDetail.token);
+            unchecked {
+                ++i;
             }
         }
     }
@@ -97,14 +100,16 @@ contract AllowanceTransfer is IAllowanceTransfer, EIP712 {
     function lockdown(TokenSpenderPair[] calldata approvals) external {
         address owner = msg.sender;
         // Revoke allowances for each pair of spenders and tokens.
-        unchecked {
-            uint256 length = approvals.length;
-            for (uint256 i = 0; i < length; ++i) {
-                address token = approvals[i].token;
-                address spender = approvals[i].spender;
 
-                allowance[owner][token][spender].amount = 0;
-                emit Lockdown(owner, token, spender);
+        uint256 length = approvals.length;
+        for (uint256 i = 0; i < length;) {
+            address token = approvals[i].token;
+            address spender = approvals[i].spender;
+
+            allowance[owner][token][spender].amount = 0;
+            emit Lockdown(owner, token, spender);
+            unchecked {
+                ++i;
             }
         }
     }

src/SignatureTransfer.sol

@@ -111,17 +111,19 @@ contract SignatureTransfer is ISignatureTransfer, EIP712 {
         _useUnorderedNonce(owner, permit.nonce);
         signature.verify(_hashTypedData(dataHash), owner);
 
-        unchecked {
-            for (uint256 i = 0; i < numPermitted; ++i) {
-                TokenPermissions memory permitted = permit.permitted[i];
-                uint256 requestedAmount = transferDetails[i].requestedAmount;
+        for (uint256 i = 0; i < numPermitted;) {
+            TokenPermissions memory permitted = permit.permitted[i];
+            uint256 requestedAmount = transferDetails[i].requestedAmount;
 
-                if (requestedAmount > permitted.amount) revert InvalidAmount(permitted.amount);
+            if (requestedAmount > permitted.amount) revert InvalidAmount(permitted.amount);
 
-                if (requestedAmount != 0) {
-                    // allow spender to specify which of the permitted tokens should be transferred
-                    ERC20(permitted.token).safeTransferFrom(owner, transferDetails[i].to, requestedAmount);
-                }
+            if (requestedAmount != 0) {
+                // allow spender to specify which of the permitted tokens should be transferred
+                ERC20(permitted.token).safeTransferFrom(owner, transferDetails[i].to, requestedAmount);
+            }
+
+            unchecked {
+                ++i;
             }
         }
     }

src/libraries/Allowance.sol

@@ -37,7 +37,7 @@ library Allowance {
         uint48 expiration
     ) internal {
         // If the inputted expiration is 0, the allowance only lasts the duration of the block.
-        allowed.expiration = expiration == 0 ? uint48(block.timestamp) : expiration;
+        allowed.expiration = expiration == BLOCK_TIMESTAMP_EXPIRATION ? uint48(block.timestamp) : expiration;
         allowed.amount = amount;
     }
 

src/libraries/PermitHash.sol

@@ -43,8 +43,11 @@ library PermitHash {
     function hash(IAllowanceTransfer.PermitBatch memory permitBatch) internal pure returns (bytes32) {
         uint256 numPermits = permitBatch.details.length;
         bytes32[] memory permitHashes = new bytes32[](numPermits);
-        for (uint256 i = 0; i < numPermits; ++i) {
+        for (uint256 i = 0; i < numPermits;) {
             permitHashes[i] = _hashPermitDetails(permitBatch.details[i]);
+            unchecked {
+                ++i;
+            }
         }
         return keccak256(
             abi.encode(
@@ -67,8 +70,11 @@ library PermitHash {
         uint256 numPermitted = permit.permitted.length;
         bytes32[] memory tokenPermissionHashes = new bytes32[](numPermitted);
 
-        for (uint256 i = 0; i < numPermitted; ++i) {
+        for (uint256 i = 0; i < numPermitted;) {
             tokenPermissionHashes[i] = _hashTokenPermissions(permit.permitted[i]);
+            unchecked {
+                ++i;
+            }
         }
 
         return keccak256(
@@ -104,8 +110,11 @@ library PermitHash {
         uint256 numPermitted = permit.permitted.length;
         bytes32[] memory tokenPermissionHashes = new bytes32[](numPermitted);
 
-        for (uint256 i = 0; i < numPermitted; ++i) {
+        for (uint256 i = 0; i < numPermitted;) {
             tokenPermissionHashes[i] = _hashTokenPermissions(permit.permitted[i]);
+            unchecked {
+                ++i;
+            }
         }
 
         return keccak256(