[Class modifiers] No error in CFE when class from a pre-feature library mixes in base mixin

[sgrekhov]

Test co19/LanguageFeatures/Class-modifiers/versioning_A02_t04 fails on CFE when class from a pre-feature library mixes in base mixin from a post-feature. All expected errors below are missed in CFE (but reported analyzer)

// class_modifiers_lib.dart
// @dart=3.0
base mixin class BaseMixinClass {}
abstract base mixin class AbstractBaseMixinClass {}
base mixin BaseMixin {}

// versioning_A02_t04.dart
// @dart=2.19

import "class_modifiers_lib.dart";

class WithBaseMixinClass with BaseMixinClass {}
//    ^^^^^^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

class WithAbstractBaseMixinClass with AbstractBaseMixinClass {}
//    ^^^^^^^^^^^^^^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

class WithBaseMixin with BaseMixin {}
//    ^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

abstract class AbstractWithBaseMixinClass with BaseMixinClass {}
//             ^^^^^^^^^^^^^^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

abstract class AbstractWithAbstractBaseMixinClass with AbstractBaseMixinClass {}
//             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

abstract class AbstractWithBaseMixin with BaseMixin {}
//             ^^^^^^^^^^^^^^^^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

[kallentu]

@sgrekhov This should also be fixed now with the fix from #52316

[sgrekhov]

Confirmed. Fixed. Thanx!