anchor.diff:  }
   
   class _ElementMismatchException extends AnalysisException {
  -  /**
  -   * Creates an exception to refer to the given [compilationUnit], [element],
  -   * and [cause].
  -   */
  +  /// Creates an exception to refer to the given [compilationUnit], [element],
  +  /// and [cause].
     _ElementMismatchException(
         CompilationUnitElement compilationUnit, Element element,
         [CaughtException cause = null])
  
positive.code:     }
    }
  
    /**
     * Creates an [ElementWalker] which walks the child elements of a typedef
     * element.
     */
    ElementWalker.forTypedef(GenericTypeAliasElementImpl element)
        : element = element,
          _parameters = element.parameters,
  
negative.code:         _typeParameters = element.typeParameters,
          _variables = element.fields.where(_isNotSynthetic).toList();
  
    /// Creates an [ElementWalker] which walks the child elements of a compilation
    /// unit element.
    ElementWalker.forCompilationUnit(CompilationUnitElement compilationUnit)
        : element = compilationUnit,
          _accessors = compilationUnit.accessors.where(_isNotSynthetic).toList(),
  