abstract_super_member_reference

The {0} '{1}' is always abstract in the supertype.

The analyzer produces this diagnostic when an inherited member is referenced using super, but there is no concrete implementation of the member in the superclass chain. Abstract members can't be invoked.

The following code produces this diagnostic because B doesn't inherit a concrete implementation of a:

abstract class A {
  int get a;
}
class B extends A {
  int get a => super.a;
}

Remove the invocation of the abstract member, possibly replacing it with an invocation of a concrete member.