anchor.diff:  // BSD-style license that can be found in the LICENSE file.
   
   import 'package:build/build.dart';
  -import 'package:build/experiments.dart';
   import 'package:build_modules/build_modules.dart';
   import 'package:build_test/build_test.dart';
   import 'package:build_web_compilers/build_web_compilers.dart';
  
positive.code:         addTearDown(listener.cancel);
          assets = {
            'b|lib/b.dart': '''
          // @dart=2.10
          final world = 'world';''',
            'a|lib/a.dart': r'''
          // @dart=2.10
          import 'package:b/b.dart';
          final hello = 'hello $world';
        ''',
            'a|web/index.dart': '''
          // @dart=2.10
          import "package:a/a.dart";
          void main() {
            print(hello);
  
negative.code:       ''',
          };
  
          // Set up all the other required inputs for this test.
          await testBuilderAndCollectAssets(const ModuleLibraryBuilder(), assets);
          await testBuilderAndCollectAssets(
              MetaModuleBuilder(ddcPlatform), assets);
          await testBuilderAndCollectAssets(
              MetaModuleCleanBuilder(ddcPlatform), assets);
          await testBuilderAndCollectAssets(ModuleBuilder(ddcPlatform), assets);
          await testBuilderAndCollectAssets(
              ddcKernelBuilder(BuilderOptions({}),
                  soundNullSafety: soundNullSafety),
              assets);
        });
  
        for (var trackUnusedInputs in [true, false]) {
  