unnecessary_final

Don't use final for local variables.

This rule is available as of Dart 2.7.

This rule has a quick fix available.

Incompatible rules: prefer_final_locals, prefer_final_parameters, prefer_final_in_for_each

Use var, not final, when declaring local variables.

Per Effective Dart, there are two styles in wide use. This rule enforces the var style. For the alternative style that prefers final, enable prefer_final_locals and prefer_final_in_for_each instead.

For fields, final is always recommended; see the rule prefer_final_fields.

BAD:

void badMethod() {
  final label = 'Final or var?';
  for (final char in ['v', 'a', 'r']) {
    print(char);
  }
}

GOOD:

void goodMethod() {
  var label = 'Final or var?';
  for (var char in ['v', 'a', 'r']) {
    print(char);
  }
}

To enable the unnecessary_final rule, add unnecessary_final under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - unnecessary_final

Unless stated otherwise, the documentation on this site reflects Dart 3.6.0. Page last updated on 2024-07-03. View source or report an issue.