No error in the analyzer to augment different type

[sgrekhov]

According to the augmentation libraries specification

It is a compile-time error if:

• The augmenting type and corresponding type are not the same kind: class, mixin, enum, extension, or extension type. You can't augment a class with a mixin, etc.

But the analyzer doesn't report this error. See https://github.com/dart-lang/co19/blob/master/LanguageFeatures/Augmentation-libraries/augmenting_types_A01_t02.dart

// augmenting_types_A01_t02.dart

import augment 'augmenting_types_A01_t02_lib1.dart';

class C {}

typedef CAlias = C;

// augmenting_types_A01_t02_lib1.dart
library augment 'augmenting_types_A01_t02.dart'; // I know that the new syntax is `augment library ...`

augment mixin CAlias {} // No expected error
//            ^^^^^^
// [analyzer] unspecified
// [cfe] unspecified

Tested on the edge SDK (March 25, 2024)