anchor.diff:    /// we remove the file, its library, and everything affected from [_component].
     Component _component = new Component();
   
  +  /// The [DillTarget] that is filled with [_component] libraries before
  +  /// compilation of a new library.
  +  DillTarget _dillTarget;
  +
     /// Each key is the file system URI of a library.
     /// Each value is the libraries that directly depend on the key library.
     final Map<Uri, Set<Uri>> _directLibraryDependencies = {};
  
positive.code:       _component.libraries.remove(library);
        _component.root.removeChild('${library.importUri}');
        _component.uriToSource.remove(libraryUri);
        _results.remove(library.importUri);
  
        // Recursively invalidate dependencies.
  
negative.code:   }
  
    Future<T> _runWithFrontEndContext<T>(String msg, Future<T> f()) async {
      return await CompilerContext.runWithOptions(_options, (context) {
        context.disableColors();
        return _logger.runAsync(msg, f);
  