prefer_const_literals_to_create_immutables

Prefer const literals as parameters of constructors on @immutable classes.

PREFER using const for instantiating list, map and set literals used as parameters in immutable class instantiations.

BAD:

@immutable
class A {
  A(this.v);
  final v;
}

A a1 = new A([1]);
A a2 = new A({});

GOOD:

A a1 = new A(const [1]);
A a2 = new A(const {});

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

linter:
  rules:
    - prefer_const_literals_to_create_immutables

If you're instead using the YAML map syntax to configure linter rules, add prefer_const_literals_to_create_immutables: true under linter > rules:

linter:
  rules:
    prefer_const_literals_to_create_immutables: true

Unless stated otherwise, the documentation on this site reflects Dart 3.6.2. Page last updated on 2025-01-27. View source or report an issue.