non_const_argument_for_const_parameter

Argument '{0}' must be a constant.

The analyzer produces this diagnostic when a parameter is annotated with the mustBeConst annotation and the corresponding argument is not a constant expression.

The following code produces this diagnostic on the invocation of the function f because the value of the argument passed to the function g isn't a constant:

import 'package:meta/meta.dart' show mustBeConst;

int f(int value) => g(value);

int g(@mustBeConst int value) => value + 1;

If a suitable constant is available to use, then replace the argument with a constant:

import 'package:meta/meta.dart' show mustBeConst;

const v = 3;

int f() => g(v);

int g(@mustBeConst int value) => value + 1;

Unless stated otherwise, the documentation on this site reflects Dart 3.8.0. Page last updated on 2025-05-08. View source or report an issue.