Incorrect Modifier

Severity: Low ID: incorrect-modifier

Reports modifiers that can finish without executing the modified function body or reverting.

What it does

Flags Solidity modifiers where at least one path can complete before reaching the _ placeholder. Paths that revert before _ are not flagged.

Only a path that provably reverts or otherwise halts is treated as safe: an explicit revert statement or revert(...) builtin call, and the Yul halting builtins (revert/invalid to fail, and return/stop/selfdestruct, which halt successfully without running the function body and are therefore flagged). A regular function call that might revert (e.g. require(...), an internal helper, or an external call) does not count, so a path that performs such a call and then returns without reaching _ is still flagged. This is intentionally stricter than some other tools.

Why is this bad?

A modifier that falls through before _ silently skips the function body. This can make calls look successful even though the protected action never ran.

Example

Bad

modifier onlyWhenEnabled() {
    if (enabled) {
        _;
    }
}

Good

modifier onlyWhenEnabled() {
    if (!enabled) {
        revert Disabled();
    }
    _;
}