Analysis server gives incorrect invalid override message

[leafpetersen]

Given the following three files, the command line analyzer reports no warnings (correctly, I believe):

leafp-macbookpro:tmp leafp$ ~/src/dart-repo/sdk/xcodebuild/ReleaseX64/dart-sdk/bin/dartanalyzer --strong --supermixin --show-package-warnings ~/tmp/intellij-test-directory/proxy_box.dart 
Analyzing /Users/leafp/tmp/intellij-test-directory/proxy_box.dart...
No issues found!
leafp-macbookpro:tmp leafp$ ~/src/dart-repo/sdk/xcodebuild/ReleaseX64/dart-sdk/bin/dartanalyzer --version
dartanalyzer version 1.25.0-edge.b176e7de503bcaf888b6208c14726e6e597435f1

However, opening the files in Intellij, with the same SDK build, and with an analysis_options file enabling super mixins produces the following error:

ERROR: Invalid override. The type of 'RenderTransform.applyPaintTransform' ('(RenderBox, Matrix4) → void') isn't a subtype of 'RenderProxyBoxMixin.applyPaintTransform' ('(RenderObject, Matrix4) → void'). (proxy_box.dart:16)

If I remove the covariant from RenderObject.applyPaintTransform, the command line analyzer reports the same error. I suspect the analysis server is losing track of covariant.

Note that this is specific to the code being split into files: if you combine all of the code into one file, the analysis server no longer produces an error.

object.dart

class Matrix4 {}

abstract class RenderObject {
void applyPaintTransform(covariant RenderObject child, Matrix4 transform) {
  }
}

abstract class RenderObjectWithChildMixin<ChildType extends RenderObject> extends RenderObject {
  ChildType _child;
  ChildType get child => _child;
  set child(ChildType value) {}
}

box.dart

import 'object.dart';

abstract class RenderBox extends RenderObject {
  @override
  void applyPaintTransform(RenderObject child, Matrix4 transform) {}
}

proxy_box.dart

import 'box.dart';
import 'object.dart';

abstract class RenderProxyBoxMixin extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
  @override
  void applyPaintTransform(RenderObject child, Matrix4 transform) { }

}

class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox>, RenderProxyBoxMixin {
}


class RenderTransform extends RenderProxyBox {
  @override
  void applyPaintTransform(RenderBox child, Matrix4 transform) {
  }
}

cc @bwilkerson @scheglov

[Hixie]

This may have been fixed, I just removed an // ignore near a TODO that pointed to this, and nothing broke.

[natebosch]

I don't get Invalid override anymore, now I get "The class 'RenderObjectWithChildMixin' can't be used as a mixin because it extends a class other than Object. [mixin_inherits_from_not_object]"

I think the original issue has been resolved and the new error is intentional. It happens whether or not the code is in the same library or multiple libraries and is consistent between CLI analyzer and the analysis server.

[leafpetersen]

@natebosch that error message means you don't have super mixins enabled, which is required for this to repro (if it in fact still reproduces).

[natebosch]

Ah, then I'll leave this open for now