const_initialized_with_non_constant_value_from_deferred_library

Constant values from a deferred library can't be used to initialize a 'const' variable.

The analyzer produces this diagnostic when a const variable is initialized using a const variable from a library that is imported using a deferred import. Constants are evaluated at compile time, and values from deferred libraries aren't available at compile time.

For more information, check out Lazily loading a library.

The following code produces this diagnostic because the variable pi is being initialized using the constant math.pi from the library dart:math, and dart:math is imported as a deferred library:

import 'dart:math' deferred as math;

const pi = math.pi;

If you need to reference the value of the constant from the imported library, then remove the keyword deferred:

import 'dart:math' as math;

const pi = math.pi;

If you don't need to reference the imported constant, then remove the reference:

const pi = 3.14;

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.