undefined_function

The function '{0}' isn't defined.

The analyzer produces this diagnostic when it encounters an identifier that appears to be the name of a function but either isn't defined or isn't visible in the scope in which it's being referenced.

The following code produces this diagnostic because the name emty isn't defined:

List<int> empty() => [];

void main() {
  print(emty());
}

If the identifier isn't defined, then either define it or replace it with the name of a function that is defined. The example above can be corrected by fixing the spelling of the function:

List<int> empty() => [];

void main() {
  print(empty());
}

If the function is defined but isn't visible, then you probably need to add an import or re-arrange your code to make the function visible.

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.