anchor.diff:  
     /// True if the 'dart:core' library is been summarized.
     bool isCoreLibrary = false;
  +
  +  /// True if the 'dart:core' library defining unit is been summarized.
  +  bool isCoreLibraryDefiningUnit = false;
   
     /// True is a [PartOfDirective] was found, so the unit is a part.
     bool isPartOf = false;
  
positive.code:     libraryNameOffset = node.name.offset;
      libraryNameLength = node.name.length;
      isCoreLibrary = libraryName == 'dart.core';
      libraryDocumentationComment =
          serializeDocumentation(node.documentationComment);
      libraryAnnotations = serializeAnnotations(node.metadata);
  
negative.code:     b.variables = variables;
  
      b.publicNamespace = computePublicNamespace(compilationUnit);
      if (isCoreLibraryDefiningUnit) {
        b.publicNamespace.names.add(
          UnlinkedPublicNameBuilder(
            name: 'Never',
  