undefined_setter

The setter '{0}' isn't defined for the '{1}' function type.

The setter '{0}' isn't defined for the type '{1}'.

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

The following code produces this diagnostic because there isn't a setter named z:

class C {
  int x = 0;
  void m(int y) {
    this.z = y;
  }
}

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

class C {
  int x = 0;
  void m(int y) {
    this.x = y;
  }
}

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.