anchor.diff:  
   import 'package:analyzer/dart/analysis/context_locator.dart' as api;
   import 'package:analyzer/dart/analysis/declared_variables.dart';
  -import 'package:analyzer/dart/analysis/results.dart';
   import 'package:analyzer/dart/ast/ast.dart';
   import 'package:analyzer/error/error.dart';
   import 'package:analyzer/file_system/file_system.dart';
  
positive.code: 
    PackageBundleAssembler assembler;
  
    final Map<String, ParsedUnitResult> inputParsedUnitResults = {};
    summary2.LinkedElementFactory elementFactory;
  
    // May be null.
  
negative.code:             }
  
              var partPath = partSource.fullName;
              var partParseResult = analysisDriver.parseFileSync(partPath);
              if (partParseResult == null) {
                throw ArgumentError('No parsed unit for part $partPath in $path');
              }
  