implicit_this_reference_in_initializer

The instance member '{0}' can't be accessed in an initializer.

The analyzer produces this diagnostic when it finds a reference to an instance member in a constructor's initializer list.

The following code produces this diagnostic because defaultX is an instance member:

class C {
  int x;

  C() : x = defaultX;

  int get defaultX => 0;
}

If the member can be made static, then do so:

class C {
  int x;

  C() : x = defaultX;

  static int get defaultX => 0;
}

If not, then replace the reference in the initializer with a different expression that doesn't use an instance member:

class C {
  int x;

  C() : x = 0;

  int get defaultX => 0;
}