pkg/front_end/testcases/extension_types/issue53867.dart.textual_outline.expect

extension type E1(num it) {}

extension type E2(E1 it) implements E1 {}

extension type E3(int it) implements E1 {}

extension type E4(E3 it) implements E1 {}

extension type E5(E3 it) implements E2 {}

extension type E6(E2 it) implements E3 {}

extension type E7(String it) implements E1 {}