|  | library test; | 
|  | // | 
|  | // Problems in library: | 
|  | // | 
|  | // pkg/front_end/testcases/inference/circular_method_inference.dart:12:16: Error: 'A' is a supertype of itself. | 
|  | // abstract class A extends B { | 
|  | //                ^ | 
|  | // | 
|  | // pkg/front_end/testcases/inference/circular_method_inference.dart:16:16: Error: 'B' is a supertype of itself. | 
|  | // abstract class B extends A { | 
|  | //                ^ | 
|  | // | 
|  | import self as self; | 
|  | import "dart:core" as core; | 
|  |  | 
|  | abstract class A extends core::Object { | 
|  | synthetic constructor •() → self::A | 
|  | : super core::Object::•() | 
|  | ; | 
|  | abstract method f(dynamic x) → dynamic; | 
|  | } | 
|  | abstract class B extends core::Object { | 
|  | synthetic constructor •() → self::B | 
|  | : super core::Object::•() | 
|  | ; | 
|  | abstract method f(dynamic x) → dynamic; | 
|  | } | 
|  | static method main() → dynamic {} |