anchor.diff:      var sourceFile = new SourceFile(
           entryPointFile.getAbsolutePath(),
           entryPointImport,
  -        resolvedUnit);
  +        resolvedUnit.element);
       List<SourceFile> visited = <SourceFile>[];
       List<SourceFile> toVisit = <SourceFile>[sourceFile];
   
  
positive.code: 
      var nextCompilationUnit = context
          .resolveCompilationUnit(source, context.computeLibraryElement(source));
      if (uri.startsWith(PACKAGE_PREFIX)) {
        toVisit.add(new SourceFile(source.toString(), uri, nextCompilationUnit));
      } else { // relative import.
        var newImport;
        if (isSystem) {
          newImport = systemImport; // original uri
        } else if (isPart) {
          newImport = currentFile.entryPointImport;
        } else {
          // relative import
          String import = currentFile.entryPointImport.
  
negative.code:         }
          newImport = '$import/$uri';
        }
        toVisit.add(new SourceFile(
            source.toString(), newImport, nextCompilationUnit.element));
      }
    }
  }
  