feat(forge-lint): [claude] check for unwrapped modifiers

[0xClandestine]

Motivation

Coauthored by Claude 4 Opus Max

Modifiers in Solidity that contain logic directly in their body can lead to code duplication when used across multiple functions. Since modifiers are inlined at compile time, any logic within them is duplicated for each function that uses the modifier increasing contract size and deployment cost. A common best practice is to extract modifier logic into internal functions that can be called from within the modifier, reducing code duplication and contract size.

Solution

This PR adds a new gas optimization lint unwrapped-modifier-logic that detects when modifiers contain logic directly in their body instead of using internal/private/public functions.

The lint checks for modifiers that contain any statements other than:

• Direct calls to internal/private/public functions.
• The placeholder _;

Example of code that triggers the lint:

modifier onlyOwner() {
    require(msg.sender == owner, "Not owner"); // Unwrapped logic
    _;
}

Recommended pattern:

modifier onlyOwner() {
    _checkOwner(); // Wrapped in internal function
    _;
}

function _checkOwner() internal view {
    require(msg.sender == owner, "Not owner");
}

PR Checklist

• Added Tests - Created testdata/ModifierLogic.sol and testdata/ModifierLogic.stderr with comprehensive test cases
• Added Documentation - Need to add lint documentation to the Foundry book under the gas optimization section
• Breaking changes - No breaking changes, this is a new lint rule

[grandizzy]

thank you, makes sense. left some nits, pending @0xrusowsky @DaniPopes review

[grandizzy]

can be simplified to

fn is_valid_expr(expr: &solar_ast::Expr<'_>) -> bool {
    if let ExprKind::Call(func_expr, _) = &expr.kind
        && let ExprKind::Ident(ident) = &func_expr.kind
    {
        return !matches!(ident.name.as_str(), "require" | "assert");
    }
    false
}

[0xClandestine]

e75f687

[grandizzy]

can be simplified to

let Some(body) = &func.body else { return };

[0xClandestine]

e75f687

[0xrusowsky]

overall the PR looks good, however i'd like to hold it back until we merge:

• feat(forge-lint): new LateLintPass + support code snippets #10846

and then make it do a fix suggestion