only-used-in-recursion

Disallow parameters used only to calculate their own recursive argument

A parameter read only to calculate its corresponding recursive argument does not affect the result.
Instead, you SHOULD remove the parameter and its argument from every recursive call.

- Category: suspicious
- Level: warning
- Fix: none
- Scope: module

Reported

function depth(remaining: int32, unused: int32): int32 {
    if (remaining === 0) {
        return 0;
    }

    return depth(remaining - 1, unused);
}
Accepted

function depth(remaining: int32): int32 {
    if (remaining === 0) {
        return 0;
    }

    return depth(remaining - 1);
}
Prior art

- Clippy · onlyusedinrecursion
- Oxc · only-used-in-recursion

language/linter/src/rules/suspicious/onlyusedinrecursion.rs:7