Root + Impact

Description

The import {IERC20} at line 6 is declared but never referenced in the contract, which inherits directly from ERC20 (providing IERC20 interface) and does not require the explicit import for implementation. Similarly, the custom error RaiseBoxFaucet_CannotClaimAnymoreFaucetToday() is defined but unused in any revert statements, suggesting it was intended for a daily limit check but never implemented.

Unused imports and errors increase the contract's size, leading to higher gas for deployment and storage. They also clutter the codebase, making audits more time-consuming as reviewers must verify irrelevance.

Risk

Likelihood:

• High: Common in iterative development where features are planned but discarded without cleanup.

• Easily overlooked in large contracts with many imports.

Impact:

• Low: Negligible runtime effects, but ~0.1-1% increase in deployment gas from extra bytecode.

• Maintenance burden: Clutter slows reviews and may hide real issues.

Proof of Concept

The following Foundry test confirms the import and error are unused: Compilation succeeds, but static analysis (e.g., Slither) flags them, and the contract functions without referencing either.

Run Slither for verification:

Expected output flags the import and error as unused.

To simulate, add a test that compiles the contract and verifies no usage:

Explanation

• Setup: Deploys the contract, which compiles despite unused elements.

• Issue Demonstration: Slither detects "unused-import" for IERC20 and unused custom error. Runtime tests pass, but static analysis confirms bloat.

• Result: The contract works, but unused code adds unnecessary size, verifiable via forge inspect RaiseBoxFaucet bytecode showing extra bytes.

• The test highlights the elements without crashing, proving they are dead code.

Recommended Mitigation

Remove the unused import and error declaration to streamline the code and reduce bytecode size.