[FEAT] Build Zero-Allocation ERC-20 Permit Processor in Yul

[mijinummi]

Labels: medium-difficulty, yul, tokens, gasguard
Difficulty: Medium
Module: contracts/tokens/

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🧠 Concept

Construct an inline assembly ERC-20 permit caller that formats EIP-2612 permit calls directly in memory without using high-level abi.encodeWithSelector.

⚠️ Problem

Standard permit wrappers allocate dynamic memory for call data, generating excessive mstore operations and expanding memory bounds prior to signature submission.

📁 Implementation Scope

• contracts/tokens/YulPermitHandler.sol
• test/tokens/YulPermitHandler.test.ts

🛠️ Requirements

1. Pack permit(address,address,uint256,uint256,uint8,bytes32,bytes32) selector and arguments directly into scratch memory using Yul.
2. Execute low-level call to target token contract and evaluate success return status.

🎯 Acceptance Criteria

• Executes ERC-20 permit approvals with lower gas than standard library helpers.
• Handles failed permit calls gracefully using custom error returns.

[priscannanna85-lgtm]

@priscannanna85-lgtm has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello Maintainer, I've reviewed the issue and have a clear understanding of the requirements. I'd be glad to work on it if assigned.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @priscannanna85-lgtm to this issue.

[lishmanTech]

@lishmanTech has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello

Let me implement this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @lishmanTech to this issue.

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Congratulations, @lishmanTech! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@lishmanTech's PR #719 was approved and merged by @mijinummi.

🏆 @lishmanTech: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (449 total points). Track your full progress on GrantFox.

👏 Great work, @lishmanTech! Keep contributing to MDTechLabs.

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