anchor.diff:  /// [ComparisonNode] representing them.
   Future<ComparisonNode> analyzePackage(
       List<Uri> inputs, Uri packagesFileUri, Uri platformUri) async {
  -  bool errorOccurred = false;
  +  var errors = <CompilationMessage>[];
     var component = await kernelForComponent(
  -      inputs,
  -      _makeCompilerOptions(packagesFileUri, platformUri, (_) {
  -        errorOccurred = true;
  -      }));
  -  if (errorOccurred) {
  -    return ComparisonNode('Error occurred');
  +      inputs, _makeCompilerOptions(packagesFileUri, platformUri, errors.add));
  +  if (errors.isNotEmpty) {
  +    return ComparisonNode(
  +        'Error occurred', errors.map(_compilationMessageToNode).toList());
     }
     var libraryNodes = <ComparisonNode>[];
     var visitor = _KernelVisitor(libraryNodes);
  
positive.code:     }
    }
    return ComparisonNode.sorted('Component', libraryNodes);
  }
  
  CompilerOptions _makeCompilerOptions(
  
negative.code: import 'dart:async';
  
  import 'package:analyzer_fe_comparison/src/comparison_node.dart';
  import 'package:front_end/src/api_prototype/compilation_message.dart';
  import 'package:front_end/src/api_prototype/compiler_options.dart';
  import 'package:front_end/src/api_prototype/kernel_generator.dart';
  import 'package:front_end/src/api_prototype/standard_file_system.dart';
  