Extension type with generic

[PlugFox]

It is impossible to use the library if an extension type contains generics. For extension types without generics, it works fine (at the master branch only).

• pubspec.yaml

  dev_dependencies:
  # https://github.com/dart-lang/mockito/issues/732
  # https://github.com/dart-lang/mockito/pull/738
  # https://github.com/dart-lang/mockito/issues/755
  mockito:
  git:
    url: https://github.com/dart-lang/mockito.git
    ref: master

• example.dart

  
  import 'dart:async';

import 'package:mockito/annotations.dart';

extension type ET$Generic(Stream ) implements Stream { ET$Generic filter() => ET$Generic(transform(StreamTransformer<T, S>.fromHandlers( handleData: (data, sink) => switch (data) { S valid => sink.add(valid), => null, }, ))); }

abstract interface class Interface { abstract final ET$Generic stream; }

@GenerateMocks([Interface]) void main() {}

- output
```log
Built build_runner:build_runner.
[INFO] Generating build script completed, took 129ms
[INFO] Reading cached asset graph completed, took 46ms
[INFO] Checking for updates since last build completed, took 328ms
[SEVERE] mockito:mockBuilder on test/unit/example.dart:

Bad state: T extends num not found, scopes: [{}]
package:mockito/src/builder.dart 2024:8                      _MockClassInfo._lookupTypeParameter
package:mockito/src/builder.dart 2162:22                     _MockClassInfo._typeReference.<fn>
package:code_builder/src/specs/type_reference.g.dart 164:33  _$TypeReferenceBuilder.update
package:code_builder/src/specs/type_reference.g.dart 22:36   new _$TypeReference
package:mockito/src/builder.dart 2160:14                     _MockClassInfo._typeReference
package:mockito/src/builder.dart 1527:27                     _MockClassInfo._dummyValue
package:mockito/src/builder.dart 1650:11                     _MockClassInfo._dummyValueImplementing
package:mockito/src/builder.dart 1547:12                     _MockClassInfo._dummyValue
package:mockito/src/builder.dart 1945:24                     _MockClassInfo._buildOverridingGetter
package:mockito/src/builder.dart 1222:36                     _MockClassInfo.fieldOverrides.<fn>
package:code_builder/src/specs/method.g.dart 323:33          _$MethodBuilder.update
package:code_builder/src/specs/method.g.dart 38:29           new _$Method
package:mockito/src/builder.dart 1222:15                     _MockClassInfo.fieldOverrides
dart:core                                                    List.addAll
package:built_collection/src/list/list_builder.dart 98:14    ListBuilder.addAll
package:mockito/src/builder.dart 1180:28                     _MockClassInfo._buildMockClass.<fn>.<fn>
package:mockito/src/builder.dart 2069:24                     _MockClassInfo._withTypeParameters
package:mockito/src/builder.dart 1134:7                      _MockClassInfo._buildMockClass.<fn>
package:code_builder/src/specs/class.g.dart 345:33           _$ClassBuilder.update
package:code_builder/src/specs/class.g.dart 40:28            new _$Class
package:mockito/src/builder.dart 1112:12                     _MockClassInfo._buildMockClass
package:mockito/src/builder.dart 1058:9                      new _MockLibraryInfo
package:mockito/src/builder.dart 94:29                       MockBuilder.build

[INFO] Running build completed, took 384ms
[INFO] Caching finalized dependency graph completed, took 32ms
[SEVERE] Failed after 421ms
make: *** [generate] Error 1