no_equal_then_else

v1.0.0 Warning Control Flow

This rule flags an if/else or conditional expression whose branches are identical. If both branches do the same thing, the condition decides nothing.

Why use this rule

Two identical branches mean one of two things: a branch was meant to differ and does not — the usual case, and a real bug — or the branching is dead weight that should collapse to a single statement.

The shape appears through copy-paste: the second branch is duplicated from the first with the intent to edit it, and the edit never happens. Nothing about it is a type error, so it survives review easily.

See also: Dart: branches

Don’t

if (isAdmin) {
  showDashboard();
} else {
  showDashboard();   // the condition changes nothing
}

final label = isActive ? 'on' : 'on';

Do

Make the branches differ, or drop the condition:

showDashboard();

Known limitations

Branches are compared by source text, with a single-statement block reduced to that statement so { f(); } and f(); compare equal. Two branches that compute the same result by different code are not reported — that is beyond what a lint can judge.

An else if chain is skipped: comparing the first branch against a whole nested if says nothing useful. Two empty branches are skipped too, since that is usually code mid-way through being written.

Configuration

This rule is in the recommended preset, so it is on with preset: recommended or preset: opinionated.

To turn it off:

many_lints.yaml

rules:
  no_equal_then_else: false

To keep the rule on but skip certain paths, use per-rule exclude.

Related rules

• no_equal_conditions — Flag an if/else-if chain that repeats a condition.
• no_equal_switch_case — Flag two switch branches with identical bodies.
• avoid_redundant_else — Drop the else when the if branch always exits.
• avoid_cascade_after_if_null — Detect cascades after if-null operators without parentheses.