prefer_const_constructors

Prefer const with constant constructors.

PREFER using const for instantiating constant constructors.

If a constructor can be invoked as const to produce a canonicalized instance, it's preferable to do so.

BAD:

class A {
  const A();
}

void accessA() {
  A a = new A();
}

GOOD:

class A {
  const A();
}

void accessA() {
  A a = const A();
}

GOOD:

class A {
  final int x;

  const A(this.x);
}

A foo(int x) => new A(x);

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

linter:
  rules:
    - prefer_const_constructors

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

linter:
  rules:
    prefer_const_constructors: true

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-03-07. View source or report an issue.