the parameter `field` is notcloneable false positive

[Lurchfresser]

Describe the bug
Extending a class with a custom constructor always produces the following error:
"E The class MyExtendingModel requested a copyWith implementation, yet the parameter field is not
cloneable."

To Reproduce

1. Make a new dart project.
2. Add this to pubspec.yaml:

dependencies:
  flutter:
    sdk: flutter
  freezed_annotation: ^3.0.0

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_lints: ^5.0.0
  build_runner: ^2.10.4
  freezed: ^3.2.3 

paste this in your main.dart:

import 'package:freezed_annotation/freezed_annotation.dart';

part 'main.freezed.dart';

void main() {}

class NonConstConstructor {
  // public field to demonstrate this.field` is accessible from the copyWith method
  final String field;
  NonConstConstructor(this.field) {
    print('Non-const constructor called with field: $field');
  }
}

// copy with is disabled
@Freezed(copyWith: false)
class MyExtendingModel extends NonConstConstructor with _$MyExtendingModel {
  MyExtendingModel(super.field);
}

3. run:
   dart run build_runner build
4. output:

Building package executable... (1.5s)
Built build_runner:build_runner.
0s freezed on 1 input: 1 skipped                                                                             
                                                                                                             
lib/main.dart freezed                                                                                        
E The class MyExtendingModel requested a copyWith implementation, yet the parameter `field` is not           
  cloneable.                                                                                                 
                                                                                                             
  To fix, either:                                                                                            
  - Disable copyWith using @Freezed(copyWith: false)                                                         
  - Make `field` optional                                                                                    
  - Make sure `this.field` is accessible from the copyWith method                                            
                                                                                                             
  package:build_runner_test/main.dart:15:7                                                                   
     ╷                                                                                                       
  15 │ class MyExtendingModel extends NonConstConstructor with _$MyExtendingModel {                          
     │       ^^^^^^^^^^^^^^^^                                                                                
     ╵                                                                                                       
Log overflowed the console, switching to line-by-line logging.
  Failed to build with build_runner/jit in 2s; wrote 0 outputs.

Expected behavior
The field is accessible and also copy with is disabled. This should produce valid code

[Malnen]

You can check if this PR resolves problem #1296
It would be nice if this was merged

[MeyneAtHuth]

I checked it. It did not resolve the issue. I added this

dependency_overrides:
  freezed:
    git:
      url: https://github.com/Malnen/freezed.git
      ref: master
      path: packages/freezed
  freezed_annotation:
    git:
      url: https://github.com/Malnen/freezed.git
      path: packages/freezed_annotation
      ref: master

and this

dependency_overrides:
  freezed:
    git:
      url: https://github.com/Malnen/freezed.git
      ref: 6c6243f1c6085c845b7a5c257ab6b822cafb93c4
      path: packages/freezed
  freezed_annotation:
    git:
      url: https://github.com/Malnen/freezed.git
      path: packages/freezed_annotation
      ref: 6c6243f1c6085c845b7a5c257ab6b822cafb93c4

to my pubspec.yaml and still got the same issue.

[Malnen]

OK, so the base class also needs to be freezed class. When I changed it to
@Freezed(copyWith: false)
class NonConstConstructor with _$NonConstConstructor
everything worked fine. But this only works on my PR or earlier versions of freezed 3.0.

[Lurchfresser]

That would be a great fix. Do you know, when PRs get usually merged?

[Malnen]

Unfortunately, I don't know, this PR has been hanging for almost 3 months :(

[Lurchfresser]

I just found a workaround for me.

import 'package:freezed_annotation/freezed_annotation.dart';

part 'main.freezed.dart';

void main() {}

@freezed
class NonConstConstructor with _$NonConstConstructor {
  // public field to demonstrate this.field` is accessible from the copyWith method
  @override
  final String field;
  NonConstConstructor(this.field) {
    print('Non-const constructor called with field: $field');
  }
}

// copy with is enabled
@freezed
class MyExtendingModel extends NonConstConstructor with _$MyExtendingModel {
  MyExtendingModel._(super.field);

  factory MyExtendingModel(String field) = _MyExtendingModel;
}

Using the factory constructor weirdly works. Then I can also generate a copy with method. Thanks for the tip, that the base class also needs to be a freezed class.