feat: redesign bank precompile for erc20 support

CHANGELOG.md

@@ -16,6 +16,7 @@
 
 - [\#589](https://github.com/cosmos/evm/pull/589) Remove parallelization blockers via migration from transient to object store, refactoring of gas, indexing, and bloom utilities.
 - [\#768](https://github.com/cosmos/evm/pull/768) Added ICS-02 Client Router precompile
+- [\#804](https://github.com/cosmos/evm/pull/804) Bank precompile redesign.
 
 ### BUG FIXES
 

Makefile

@@ -168,7 +168,7 @@ test-unit-cover: run-tests
 	@echo "🔀 Merging evmd coverage into root coverage..."
 	@tail -n +2 evmd/coverage_evmd.txt >> coverage.txt && rm evmd/coverage_evmd.txt
 	@echo "🧹 Filtering ignored files from coverage.txt..."
-	@grep -v -E '/cmd/|/client/|/proto/|/testutil/|/mocks/|/test_.*\.go:|\.pb\.go:|\.pb\.gw\.go:|/x/[^/]+/module\.go:|/scripts/|/ibc/testing/|/version/|\.md:|\.pulsar\.go:' coverage.txt > tmp_coverage.txt && mv tmp_coverage.txt coverage.txt
+	@grep -v -E '/cmd/|/client/|/proto/|/testutil/|/mocks/|/test_.*\.go:|\.pb\.go:|\.pb\.gw\.go:|\.abi\.go:|/x/[^/]+/module\.go:|/scripts/|/ibc/testing/|/version/|\.md:|\.pulsar\.go:' coverage.txt > tmp_coverage.txt && mv tmp_coverage.txt coverage.txt
 
 test: test-unit
 

evmd/app.go

@@ -462,6 +462,7 @@ func NewExampleApp(
 			*app.StakingKeeper,
 			app.DistrKeeper,
 			app.PreciseBankKeeper,
+			app.BankKeeper,
 			&app.Erc20Keeper,
 			&app.TransferKeeper,
 			app.IBCKeeper.ChannelKeeper,

evmd/go.mod

@@ -20,7 +20,7 @@ require (
 	github.com/cosmos/evm v0.2.0
 	github.com/cosmos/gogoproto v1.7.2
 	github.com/cosmos/ibc-go/v10 v10.0.0-beta.0.0.20251027215440-22f0033d0aee
-	github.com/ethereum/go-ethereum v1.16.5
+	github.com/ethereum/go-ethereum v1.16.7
 	github.com/onsi/ginkgo/v2 v2.23.4
 	github.com/onsi/gomega v1.38.0
 	github.com/spf13/cast v1.10.0
@@ -242,6 +242,7 @@ require (
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/tyler-smith/go-bip39 v1.1.0 // indirect
 	github.com/ulikunitz/xz v0.5.15 // indirect
+	github.com/yihuang/go-abi v0.1.1 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	github.com/zeebo/errs v1.4.0 // indirect
 	github.com/zondax/golem v0.27.0 // indirect

evmd/go.sum

@@ -972,6 +972,8 @@ github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 h1:epCh84lMvA70
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7/go.mod h1:q4W45IWZaF22tdD+VEXcAWRA037jwmWEB5VWYORlTpc=
 github.com/tendermint/go-amino v0.16.0 h1:GyhmgQKvqF82e2oZeuMSp9JTN0N09emoSZlb2lyGa2E=
 github.com/tendermint/go-amino v0.16.0/go.mod h1:TQU0M1i/ImAo+tYpZi73AU3V/dKeCoMC9Sphe2ZwGME=
+github.com/test-go/testify v1.1.4 h1:Tf9lntrKUMHiXQ07qBScBTSA0dhYQlu83hswqelv1iE=
+github.com/test-go/testify v1.1.4/go.mod h1:rH7cfJo/47vWGdi4GPj16x3/t1xGOj2YxzmNQzk2ghU=
 github.com/tidwall/gjson v1.14.2/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
 github.com/tidwall/gjson v1.18.0 h1:FIDeeyB800efLX89e5a8Y0BNH+LOngJyGrIWxG2FKQY=
 github.com/tidwall/gjson v1.18.0/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
@@ -1002,6 +1004,8 @@ github.com/urfave/cli/v2 v2.27.5/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 h1:gEOO8jv9F4OT7lGCjxCBTO/36wtF6j2nSip77qHd4x4=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
+github.com/yihuang/go-abi v0.1.1 h1:5MHV/wOz0wywsb9IhaZmHLhBNAF5EzSXisPyv3gN5Rs=
+github.com/yihuang/go-abi v0.1.1/go.mod h1:btymTlqoiLCR8Gj5bppalyNPSzQYUfK6YROYsihjGS4=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=

go.mod

@@ -25,7 +25,7 @@ require (
 	github.com/cosmos/ledger-cosmos-go v0.16.0
 	github.com/creachadair/tomledit v0.0.28
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc
-	github.com/ethereum/go-ethereum v1.16.5
+	github.com/ethereum/go-ethereum v1.16.7
 	github.com/gogo/protobuf v1.3.2
 	github.com/golang/protobuf v1.5.4
 	github.com/gorilla/mux v1.8.1
@@ -46,6 +46,7 @@ require (
 	github.com/tidwall/gjson v1.18.0
 	github.com/tidwall/sjson v1.2.5
 	github.com/tyler-smith/go-bip39 v1.1.0
+	github.com/yihuang/go-abi v0.1.1
 	github.com/zondax/hid v0.9.2
 	go.uber.org/mock v0.6.0
 	golang.org/x/crypto v0.45.0
@@ -266,6 +267,7 @@ require (
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/arch v0.21.0 // indirect
 	golang.org/x/exp v0.0.0-20250506013437-ce4c2cf36ca6 // indirect
+	golang.org/x/mod v0.29.0 // indirect
 	golang.org/x/oauth2 v0.31.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/term v0.37.0 // indirect

go.sum

@@ -952,6 +952,8 @@ github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 h1:epCh84lMvA70
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7/go.mod h1:q4W45IWZaF22tdD+VEXcAWRA037jwmWEB5VWYORlTpc=
 github.com/tendermint/go-amino v0.16.0 h1:GyhmgQKvqF82e2oZeuMSp9JTN0N09emoSZlb2lyGa2E=
 github.com/tendermint/go-amino v0.16.0/go.mod h1:TQU0M1i/ImAo+tYpZi73AU3V/dKeCoMC9Sphe2ZwGME=
+github.com/test-go/testify v1.1.4 h1:Tf9lntrKUMHiXQ07qBScBTSA0dhYQlu83hswqelv1iE=
+github.com/test-go/testify v1.1.4/go.mod h1:rH7cfJo/47vWGdi4GPj16x3/t1xGOj2YxzmNQzk2ghU=
 github.com/tidwall/gjson v1.14.2/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
 github.com/tidwall/gjson v1.18.0 h1:FIDeeyB800efLX89e5a8Y0BNH+LOngJyGrIWxG2FKQY=
 github.com/tidwall/gjson v1.18.0/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
@@ -982,6 +984,8 @@ github.com/urfave/cli/v2 v2.27.5/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 h1:gEOO8jv9F4OT7lGCjxCBTO/36wtF6j2nSip77qHd4x4=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
+github.com/yihuang/go-abi v0.1.1 h1:5MHV/wOz0wywsb9IhaZmHLhBNAF5EzSXisPyv3gN5Rs=
+github.com/yihuang/go-abi v0.1.1/go.mod h1:btymTlqoiLCR8Gj5bppalyNPSzQYUfK6YROYsihjGS4=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
@@ -1089,6 +1093,8 @@ golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
+golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
 golang.org/x/net v0.0.0-20180719180050-a680a1efc54d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=

precompiles/bank/ERC20.bin

@@ -0,0 +1 @@
+60a0604052346102315761107d8038038061001981610235565b9283398101906040818303126102315780516001600160401b0381116102315781019082601f830112156102315781516001600160401b03811161021d5761006a601f8201601f1916602001610235565b9381855260208285010111610231576020815f92828096018388015e8501015201516001600160a01b03811681036102315781516001600160401b03811161021d575f54600181811c91168015610213575b60208210146101ff57601f811161019d575b50602092601f821160011461013e57928192935f92610133575b50508160011b915f199060031b1c1916175f555b608052604051610e22908161025b823960805181818161030a015281816103c10152818161048e0152818161057f0152610c660152f35b015190505f806100e8565b601f198216935f8052805f20915f5b868110610185575083600195961061016d575b505050811b015f556100fc565b01515f1960f88460031b161c191690555f8080610160565b9192602060018192868501518155019401920161014d565b5f80527f290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e563601f830160051c810191602084106101f5575b601f0160051c01905b8181106101ea57506100ce565b5f81556001016101dd565b90915081906101d4565b634e487b7160e01b5f52602260045260245ffd5b90607f16906100bc565b634e487b7160e01b5f52604160045260245ffd5b5f80fd5b6040519190601f01601f191682016001600160401b0381118382101761021d5760405256fe6080806040526004361015610012575f80fd5b5f3560e01c90816306fdde03146108a557508063095ea7b3146107f857806318160ddd1461078d57806323b872dd146105f9578063313ce567146104fb57806370a08231146103e557806376cdb03b1461037757806395d89b4114610287578063a9059cbb14610238578063c370b042146101255763dd62ed3e14610095575f80fd5b346101215760407ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121576100cc610954565b73ffffffffffffffffffffffffffffffffffffffff6100e9610977565b91165f52600160205273ffffffffffffffffffffffffffffffffffffffff60405f2091165f52602052602060405f2054604051908152f35b5f80fd5b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121576040515f5f546101628161099a565b80845290600181169081156101f6575060011461019a575b6101968361018a818503826109eb565b6040519182918261090c565b0390f35b5f8080527f290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e563939250905b8082106101dc5750909150810160200161018a61017a565b9192600181602092548385880101520191019092916101c4565b7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff001660208086019190915291151560051b8401909101915061018a905061017a565b346101215760407ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc3601126101215761027c610272610954565b6024359033610ba5565b602060405160018152f35b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121576040517f41bb0559000000000000000000000000000000000000000000000000000000008152602060048201525f81806102f160248201610aea565b038173ffffffffffffffffffffffffffffffffffffffff7f0000000000000000000000000000000000000000000000000000000000000000165afa801561036c57610196915f9161034a575b506040519182918261090c565b61036691503d805f833e61035e81836109eb565b810190610a59565b8261033d565b6040513d5f823e3d90fd5b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc36011261012157602060405173ffffffffffffffffffffffffffffffffffffffff7f0000000000000000000000000000000000000000000000000000000000000000168152f35b346101215760207ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc3601126101215761041c610954565b73ffffffffffffffffffffffffffffffffffffffff604051917fb9b092c8000000000000000000000000000000000000000000000000000000008352166004820152604060248201526020818061047560448201610aea565b038173ffffffffffffffffffffffffffffffffffffffff7f0000000000000000000000000000000000000000000000000000000000000000165afa801561036c575f906104c8575b602090604051908152f35b506020813d6020116104f3575b816104e2602093836109eb565b8101031261012157602090516104bd565b3d91506104d5565b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121576040517f3b2b3204000000000000000000000000000000000000000000000000000000008152602060048201526020818061056660248201610aea565b038173ffffffffffffffffffffffffffffffffffffffff7f0000000000000000000000000000000000000000000000000000000000000000165afa801561036c575f906105bc575b60209060ff60405191168152f35b506020813d6020116105f1575b816105d6602093836109eb565b81010312610121575160ff81168103610121576020906105ae565b3d91506105c9565b346101215760607ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc36011261012157610630610954565b610638610977565b6044359073ffffffffffffffffffffffffffffffffffffffff831692835f52600160205260405f2073ffffffffffffffffffffffffffffffffffffffff33165f5260205260405f20547fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff81106106b4575b5061027c9350610ba5565b83811061075957841561072d5733156107015761027c945f52600160205260405f2073ffffffffffffffffffffffffffffffffffffffff33165f526020528360405f2091039055846106a9565b7f94280d62000000000000000000000000000000000000000000000000000000005f525f60045260245ffd5b7fe602df05000000000000000000000000000000000000000000000000000000005f525f60045260245ffd5b83907ffb8f41b2000000000000000000000000000000000000000000000000000000005f523360045260245260445260645ffd5b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121576040517fc415db13000000000000000000000000000000000000000000000000000000008152602060048201526020818061047560248201610aea565b346101215760407ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc3601126101215761082f610954565b60243590331561072d5773ffffffffffffffffffffffffffffffffffffffff1690811561070157335f52600160205260405f20825f526020528060405f20556040519081527f8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b92560203392a3602060405160018152f35b34610121575f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc360112610121577f5b43bc99000000000000000000000000000000000000000000000000000000008152602060048201525f81806102f160248201610aea565b7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe0601f602060409481855280519182918282880152018686015e5f8582860101520116010190565b6004359073ffffffffffffffffffffffffffffffffffffffff8216820361012157565b6024359073ffffffffffffffffffffffffffffffffffffffff8216820361012157565b90600182811c921680156109e1575b60208310146109b457565b7f4e487b71000000000000000000000000000000000000000000000000000000005f52602260045260245ffd5b91607f16916109a9565b90601f7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe0910116810190811067ffffffffffffffff821117610a2c57604052565b7f4e487b71000000000000000000000000000000000000000000000000000000005f52604160045260245ffd5b6020818303126101215780519067ffffffffffffffff8211610121570181601f820112156101215780519067ffffffffffffffff8211610a2c5760405192610ac960207fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe0601f86011601856109eb565b8284526020838301011161012157815f9260208093018386015e8301015290565b905f915f5490610af98261099a565b8082529160018116908115610b6b5750600114610b14575050565b5f8080529293509091907f290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e5635b838310610b51575060209250010190565b600181602092949394548385870101520191019190610b40565b60209495507fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0091509291921683830152151560051b010190565b73ffffffffffffffffffffffffffffffffffffffff16908115610dc05773ffffffffffffffffffffffffffffffffffffffff16918215610d94576040517f1af716ba000000000000000000000000000000000000000000000000000000008152826004820152836024820152816044820152608060648201525f815f54610c2b8161099a565b908160848401526001811690815f14610d545750600114610cfc575b508060209203815f73ffffffffffffffffffffffffffffffffffffffff7f0000000000000000000000000000000000000000000000000000000000000000165af1801561036c57610cc1575b5060207fddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef91604051908152a3565b6020813d602011610cf4575b81610cda602093836109eb565b810103126101215751801515810361012157506020610c93565b3d9150610ccd565b5f8080529192507f290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e5635b818310610d3a575050810160a4019080610c47565b805483860160a40152849350602090920191600101610d25565b7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff001660a48085019190915291151560051b83019091019250819050610c47565b7fec442f05000000000000000000000000000000000000000000000000000000005f525f60045260245ffd5b7f96c6fd1e000000000000000000000000000000000000000000000000000000005f525f60045260245ffdfea26469706673582212209877ef265ed97e48971f94b7bbf60b6475123ef4a1b88d7af8ae4a8f4526564f64736f6c634300081e0033

precompiles/bank/ERC20.sol

@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+interface IBankPrecompile {
+    // queries
+    function name(string memory denom) external view returns (string memory);
+    function symbol(string memory denom) external view returns (string memory);
+    function decimals(string memory denom) external view returns (uint8);
+    function totalSupply(string memory denom) external view returns (uint256);
+    function balanceOf(address account, string memory denom) external view returns (uint256);
+
+    function transferFrom(address from, address to, uint256 value, string memory denom) external returns (bool);
+}
+
+contract ERC20 {
+    event Transfer(address indexed from, address indexed to, uint256 value);
+    event Approval(address indexed owner, address indexed spender, uint256 value);
+
+    error ERC20InvalidSender(address sender);
+    error ERC20InvalidReceiver(address receiver);
+    error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);
+    error ERC20InvalidApprover(address approver);
+    error ERC20InvalidSpender(address spender);
+
+
+    string public denom;
+    mapping(address account => mapping(address spender => uint256)) public allowance;
+
+    IBankPrecompile public immutable bank;
+
+    constructor(string memory denom_, IBankPrecompile bank_) {
+        denom = denom_;
+        bank = bank_;
+    }
+
+    function name() public view returns (string memory) {
+        return bank.name(denom);
+    }
+
+    function symbol() public view returns (string memory) {
+        return bank.symbol(denom);
+    }
+
+    function decimals() public view returns (uint8) {
+        return bank.decimals(denom);
+    }
+
+    function totalSupply() public view returns (uint256) {
+        return bank.totalSupply(denom);
+    }
+
+    function balanceOf(address account) public view returns (uint256) {
+        return bank.balanceOf(account, denom);
+    }
+
+    function transfer(address to, uint256 value) public returns (bool) {
+        _transfer(msg.sender, to, value);
+        return true;
+    }
+
+    function approve(address spender, uint256 value) public returns (bool) {
+        _approve(msg.sender, spender, value);
+        return true;
+    }
+
+    function transferFrom(address from, address to, uint256 value) public returns (bool) {
+        address spender = msg.sender;
+        _spendAllowance(from, spender, value);
+        _transfer(from, to, value);
+        return true;
+    }
+
+    function _transfer(address from, address to, uint256 value) internal {
+        if (from == address(0)) {
+            revert ERC20InvalidSender(address(0));
+        }
+        if (to == address(0)) {
+            revert ERC20InvalidReceiver(address(0));
+        }
+
+        bank.transferFrom(from, to, value, denom);
+        emit Transfer(from, to, value);
+    }
+
+    function _approve(address owner, address spender, uint256 value) internal {
+        _approve(owner, spender, value, true);
+    }
+
+    function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual {
+        if (owner == address(0)) {
+            revert ERC20InvalidApprover(address(0));
+        }
+        if (spender == address(0)) {
+            revert ERC20InvalidSpender(address(0));
+        }
+        allowance[owner][spender] = value;
+        if (emitEvent) {
+            emit Approval(owner, spender, value);
+        }
+    }
+
+    function _spendAllowance(address owner, address spender, uint256 value) internal virtual {
+        uint256 currentAllowance = allowance[owner][spender];
+        if (currentAllowance < type(uint256).max) {
+            if (currentAllowance < value) {
+                revert ERC20InsufficientAllowance(spender, currentAllowance, value);
+            }
+            unchecked {
+                _approve(owner, spender, currentAllowance - value, false);
+            }
+        }
+    }
+}