| library; | 
 | import self as self; | 
 | import "dart:core" as core; | 
 |  | 
 | class A<T extends core::Object? = dynamic> extends core::Object { | 
 |   synthetic constructor •() → self::A<self::A::T%> | 
 |     : super core::Object::•() | 
 |     ; | 
 |   method f<U extends core::Object? = dynamic>(covariant-by-class core::Map<self::A::T%, self::A::f::U%> m) → void {} | 
 | } | 
 | class B extends self::A<core::String> { | 
 |   synthetic constructor •() → self::B | 
 |     : super self::A::•() | 
 |     ; | 
 |   method f<V extends core::Object? = dynamic>(covariant-by-class core::Map<core::String, self::B::f::V%> m) → void {} | 
 | } | 
 | static method main() → dynamic {} |