anchor.diff:    bool get isNotOptional;
   
     /// Return `true` if this parameter is an optional parameter. Optional
  -  /// parameters can either be positional or named.
  +  /// parameters can either be positional or named.  Named parameters that are
  +  /// annotated with the `@required` annotation are considered optional.  Named
  +  /// parameters that are annotated with the `required` syntax are considered
  +  /// required.
     bool get isOptional;
   
     /// Return `true` if this parameter is both an optional and named parameter.
  +  /// Named parameters that are annotated with the `@required` annotation are
  +  /// considered optional.  Named parameters that are annotated with the
  +  /// `required` syntax are considered required.
     bool get isOptionalNamed;
   
     /// Return `true` if this parameter is both an optional and positional
  
positive.code:   /// Return `true` if this parameter is an initializing formal parameter.
    bool get isInitializingFormal;
  
    /// Return `true` if this parameter is a named parameter. Named parameters are
    /// always optional, even when they are annotated with the `@required`
    /// annotation.
    bool get isNamed;
  
    /// Return `true` if this parameter is a required parameter. Required
  
negative.code:   bool get isPositional;
  
    /// Return `true` if this parameter is both a required and named parameter.
    /// Named parameters that are annotated with the `@required` annotation are
    /// considered optional.  Named parameters that are annotated with the
    /// `required` syntax are considered required.
    bool get isRequiredNamed;
  
    /// Return `true` if this parameter is both a required and positional
  