diff --git a/.gas-snapshot b/.gas-snapshot
index 43709871..2e69cee2 100644
--- a/.gas-snapshot
+++ b/.gas-snapshot
@@ -16,8 +16,8 @@ testSetOwnerAsOwner() (gas: 3998)
 testFromLast20Bytes() (gas: 191)
 testFillLast12Bytes() (gas: 223)
 testFailDoubleDeploySameBytecode() (gas: 277076930206699)
-testDeployERC20() (gas: 873896)
-testFailDoubleDeployDifferentBytecode() (gas: 277076930214885)
+testDeployERC20() (gas: 863534)
+testFailDoubleDeployDifferentBytecode() (gas: 277076930214685)
 testFailBoundMinBiggerThanMax() (gas: 309)
 testBound() (gas: 5520)
 testFailSafeBatchTransferFromToRevertingERC1155Recipient() (gas: 1041163)
@@ -58,34 +58,34 @@ testFailBatchBurnWithArrayLengthMismatch() (gas: 131065)
 testFailMintToZero() (gas: 29205)
 testSafeTransferFromSelf() (gas: 59828)
 testFailMintToWrongReturnDataERC155Recipient() (gas: 263102)
-testInfiniteApproveTransferFrom() (gas: 387796)
+testInfiniteApproveTransferFrom() (gas: 387818)
 testApprove() (gas: 26558)
-testMetaData() (gas: 6966)
-testTransferFrom() (gas: 388134)
-testFailTransferFromInsufficientBalance() (gas: 359401)
-testFailPermitPastDeadline() (gas: 1489)
-testFailPermitReplay() (gas: 59241)
-testMint() (gas: 49180)
-testFailTransferFromInsufficientAllowance() (gas: 358925)
-testTransfer() (gas: 75628)
-testBurn() (gas: 52492)
-testPermit() (gas: 56074)
-testFailTransferInsufficientBalance() (gas: 48240)
-testFailPermitBadDeadline() (gas: 29778)
-testFailPermitBadNonce() (gas: 29728)
+testMetaData() (gas: 6922)
+testTransferFrom() (gas: 388156)
+testFailTransferFromInsufficientBalance() (gas: 359467)
+testFailPermitPastDeadline() (gas: 1467)
+testFailPermitReplay() (gas: 59219)
+testMint() (gas: 49224)
+testFailTransferFromInsufficientAllowance() (gas: 358991)
+testTransfer() (gas: 75650)
+testBurn() (gas: 52536)
+testPermit() (gas: 56030)
+testFailTransferInsufficientBalance() (gas: 48306)
+testFailPermitBadDeadline() (gas: 29756)
+testFailPermitBadNonce() (gas: 29706)
 testFailRedeemWithNoShareAmount() (gas: 7821)
-testFailRedeemWithNotEnoughShareAmount() (gas: 172439)
+testFailRedeemWithNotEnoughShareAmount() (gas: 172548)
 testFailWithdrawWithNoUnderlyingAmount() (gas: 7817)
-testFailMintWithNoApproval() (gas: 52260)
-testMetaData() (gas: 7078)
-testFailDepositWithNotEnoughApproval() (gas: 123824)
+testFailMintWithNoApproval() (gas: 52305)
+testMetaData() (gas: 7034)
+testFailDepositWithNotEnoughApproval() (gas: 123955)
 testFailRedeemZero() (gas: 5645)
-testFailWithdrawWithNotEnoughUnderlyingAmount() (gas: 172441)
-testFailDepositZero() (gas: 3212)
-testMultipleMintDepositRedeemWithdraw() (gas: 1329713)
-testWithdrawZero() (gas: 44408)
-testFailDepositWithNoApproval() (gas: 52232)
-testMintZero() (gas: 44692)
+testFailWithdrawWithNotEnoughUnderlyingAmount() (gas: 172550)
+testFailDepositZero() (gas: 3277)
+testMultipleMintDepositRedeemWithdraw() (gas: 1329515)
+testWithdrawZero() (gas: 44364)
+testFailDepositWithNoApproval() (gas: 52297)
+testMintZero() (gas: 44693)
 testSafeTransferFromToERC721Recipient() (gas: 885885)
 testFailSafeMintToERC721RecipientWithWrongReturnDataWithData() (gas: 163605)
 testApprove() (gas: 73904)
@@ -200,7 +200,7 @@ testTransferWithNonContract() (gas: 3075)
 testApproveWithTransferFromSelf() (gas: 26416)
 testTransferWithTransferFromSelf() (gas: 28182)
 testFailTransferETHToContractWithoutFallback() (gas: 7222)
-testPartialWithdraw() (gas: 68803)
-testDeposit() (gas: 58804)
-testFallbackDeposit() (gas: 59068)
-testWithdraw() (gas: 68737)
+testPartialWithdraw() (gas: 68781)
+testDeposit() (gas: 58760)
+testFallbackDeposit() (gas: 59024)
+testWithdraw() (gas: 68715)
diff --git a/src/tokens/ERC20.sol b/src/tokens/ERC20.sol
index 9d6fe64f..d7d26c95 100644
--- a/src/tokens/ERC20.sol
+++ b/src/tokens/ERC20.sol
@@ -38,7 +38,7 @@ abstract contract ERC20 {
                              EIP-2612 STORAGE
     //////////////////////////////////////////////////////////////*/
 
-    bytes32 public constant PERMIT_TYPEHASH =
+    bytes32 internal constant PERMIT_TYPEHASH =
         keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
 
     uint256 internal immutable INITIAL_CHAIN_ID;