abstract_field_initializer

Abstract fields can't have initializers.

The analyzer produces this diagnostic when a field that has the abstract modifier also has an initializer.

The following code produces this diagnostic because f is marked as abstract and has an initializer:

abstract class C {
  abstract int f = 0;
}

The following code produces this diagnostic because f is marked as abstract and there's an initializer in the constructor:

abstract class C {
  abstract int f;

  C() : f = 0;
}

If the field must be abstract, then remove the initializer:

abstract class C {
  abstract int f;
}

If the field isn't required to be abstract, then remove the keyword:

abstract class C {
  int f = 0;
}