ifs-same-cond

Flags an if / else if chain where two arms test the same condition.

Rationale

A repeated condition in a chain is almost always a copy-paste error: the earlier arm always matches first, so the later arm with the identical condition is unreachable. What the author meant to write was a different condition in the second arm.

What triggers

The rule fires when two arms of the same if / else if chain have structurally equal conditions — formatting and whitespace are ignored, so a == b matches a==b. The duplicate need not be adjacent — if (a) … else if (b) … else if (a) … is flagged too. Each repeated arm is reported once.

What does not trigger

• Two separate if statements that happen to share a condition. They are not one chain — the first can fall through to the second, so the repetition may be intentional.
• Any condition containing a call (foo()) or a new. A call may have side effects, so two textually-identical calls need not evaluate to the same value on each run.

Example

if (status == OK) {
    handleOk();
} else if (status == OK) { // can never run — likely meant `status == ERROR`
    handleError();
}

No auto-fix — the rule can’t know what the second condition was meant to be.