anchor.diff:   * Writes the canonical text presentation of elements.
    */
   class _ElementWriter {
  +  final String selfUriStr;
     final bool withCodeRanges;
     final bool withExportScope;
     final bool withFullyResolvedAst;
  
positive.code:   bool annotateNullability: false,
  }) {
    var writer = new _ElementWriter(
        withCodeRanges: withCodeRanges,
        withConstElements: withConstElements,
        withExportScope: withExportScope,
        withFullyResolvedAst: withFullyResolvedAst,
        withOffsets: withOffsets,
        withSyntheticAccessors: withSyntheticAccessors,
        withSyntheticFields: withSyntheticFields,
        withTypes: withTypes,
        annotateNullability: annotateNullability);
    writer.writeLibraryElement(library);
  
    String actualText = writer.buffer.toString();
  
negative.code: 
    String indent = '';
  
    _ElementWriter({
      this.selfUriStr,
      this.withCodeRanges,
      this.withConstElements: true,
      this.withExportScope: false,
      this.withFullyResolvedAst: false,
      this.withOffsets: false,
      this.withSyntheticAccessors: false,
      this.withSyntheticFields: false,
      this.withTypes: false,
      this.annotateNullability: false,
    });
  
    bool isDynamicType(DartType type) => type is DynamicTypeImpl;
  
  