anchor.diff:          .map((trait) => compileType(context, trait));
       final implInnerDeclarationIds =
           impls.expand((impl) => impl.innerDeclarationIds);
  -    final methodOverrides = implInnerDeclarationIds
  -        .where((id) => id.isFunction)
  +    final implMethodIds =
  +        implInnerDeclarationIds.where((id) => id.isFunction).toList();
  +    final methodOverrides = implMethodIds
           .map((id) => Tuple2(id, getFunctionDeclarationHir(context, id)))
           .map((values) {
         final id = values.first;
  
positive.code:       ))
        ..fields.addAll(properties)
        ..methods.addAll(methods)
        ..methods.addAll(methodOverrides));
    },
  );
  
negative.code: import 'package:code_builder/code_builder.dart' as dart;
  import 'package:compiler/compiler.dart';
  import 'package:parser/parser.dart';
  import 'package:dartx/dartx.dart';
  
  import '../body.dart';
  import '../constants.dart';
  