invalid_use_of_visible_for_testing_member

The member '{0}' can only be used within '{1}' or a test.

The analyzer produces this diagnostic when a member annotated with @visibleForTesting is referenced anywhere other than the library in which it is declared or in a library in the test directory.

Given a file c.dart that contains the following:

import 'package:meta/meta.dart';
​
class C {
  @visibleForTesting
  void m() {}
}

The following code, when not inside the test directory, produces this diagnostic because the method m is marked as being visible only for tests:

import 'c.dart';
​
void f(C c) {
  c.m();
}

If the annotated member should not be referenced outside of tests, then remove the reference:

import 'c.dart';
​
void f(C c) {}

If it's OK to reference the annotated member outside of tests, then remove the annotation:

class C {
  void m() {}
}