| library; | 
 | // | 
 | // Problems in library: | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:12:7: Error: The implementation of '+' in the non-abstract class 'B' does not conform to its interface. | 
 | // class B extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:6:18: Context: The parameter 'b' of the method 'A.+' has type 'B', which does not match the corresponding type, 'A', in the overridden method, 'B.+'. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a supertype of 'A', or, for a covariant parameter, a subtype. | 
 | //   A operator +(B b) => new A(); | 
 | //                  ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:13:14: Context: This is the overridden method ('+'). | 
 | //   A operator +(A a); | 
 | //              ^ | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:12:7: Error: The implementation of 'unary-' in the non-abstract class 'B' does not conform to its interface. | 
 | // class B extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:7:14: Context: The return type of the method 'A.unary-' is 'A', which does not match the return type, 'B', of the overridden method, 'B.unary-'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a subtype of 'B'. | 
 | //   A operator -() => new A(); | 
 | //              ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:14:14: Context: This is the overridden method ('unary-'). | 
 | //   B operator -(); | 
 | //              ^ | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:12:7: Error: The implementation of '[]' in the non-abstract class 'B' does not conform to its interface. | 
 | // class B extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:8:19: Context: The parameter 'b' of the method 'A.[]' has type 'B', which does not match the corresponding type, 'A', in the overridden method, 'B.[]'. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a supertype of 'A', or, for a covariant parameter, a subtype. | 
 | //   A operator [](B b) => new A(); | 
 | //                   ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:15:14: Context: This is the overridden method ('[]'). | 
 | //   A operator [](A a); | 
 | //              ^ | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:12:7: Error: The implementation of '[]=' in the non-abstract class 'B' does not conform to its interface. | 
 | // class B extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:9:23: Context: The parameter 'b1' of the method 'A.[]=' has type 'B', which does not match the corresponding type, 'A', in the overridden method, 'B.[]='. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a supertype of 'A', or, for a covariant parameter, a subtype. | 
 | //   void operator []=(B b1, B b2) {} | 
 | //                       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:16:17: Context: This is the overridden method ('[]='). | 
 | //   void operator []=(A a, B b); | 
 | //                 ^ | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:19:7: Error: The implementation of '[]' in the non-abstract class 'C' does not conform to its interface. | 
 | // class C extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:8:14: Context: The return type of the method 'A.[]' is 'A', which does not match the return type, 'B', of the overridden method, 'C.[]'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a subtype of 'B'. | 
 | //   A operator [](B b) => new A(); | 
 | //              ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:20:14: Context: This is the overridden method ('[]'). | 
 | //   B operator [](B b); | 
 | //              ^ | 
 | // | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:19:7: Error: The implementation of '[]=' in the non-abstract class 'C' does not conform to its interface. | 
 | // class C extends A { | 
 | //       ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:9:29: Context: The parameter 'b2' of the method 'A.[]=' has type 'B', which does not match the corresponding type, 'A', in the overridden method, 'C.[]='. | 
 | //  - 'B' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | //  - 'A' is from 'pkg/front_end/testcases/general/abstract_operator_override.dart'. | 
 | // Change to a supertype of 'A', or, for a covariant parameter, a subtype. | 
 | //   void operator []=(B b1, B b2) {} | 
 | //                             ^ | 
 | // pkg/front_end/testcases/general/abstract_operator_override.dart:21:17: Context: This is the overridden method ('[]='). | 
 | //   void operator []=(B b, A a); | 
 | //                 ^ | 
 | // | 
 | import self as self; | 
 | import "dart:core" as core; | 
 |  | 
 | class A extends core::Object { | 
 |   synthetic constructor •() → self::A | 
 |     : super core::Object::•() | 
 |     ; | 
 |   operator +(self::B b) → self::A | 
 |     return new self::A::•(); | 
 |   operator unary-() → self::A | 
 |     return new self::A::•(); | 
 |   operator [](self::B b) → self::A | 
 |     return new self::A::•(); | 
 |   operator []=(self::B b1, self::B b2) → void {} | 
 | } | 
 | class B extends self::A { | 
 |   synthetic constructor •() → self::B | 
 |     : super self::A::•() | 
 |     ; | 
 |   abstract erroneous operator +(self::A a) → self::A; | 
 |   abstract erroneous operator unary-() → self::B; | 
 |   abstract erroneous operator [](self::A a) → self::A; | 
 |   abstract erroneous operator []=(self::A a, self::B b) → void; | 
 | } | 
 | class C extends self::A { | 
 |   synthetic constructor •() → self::C | 
 |     : super self::A::•() | 
 |     ; | 
 |   abstract erroneous operator [](self::B b) → self::B; | 
 |   abstract erroneous operator []=(self::B b, self::A a) → void; | 
 | } | 
 | static method main() → dynamic {} |