anchor.diff:    ///
     /// If the [style] argument is null, the text will use the style from the
     /// closest enclosing [DefaultTextStyle].
  +  ///
  +  /// The [data] parameter must not be null.
     const Text(this.data, {
       Key key,
       this.style,
  
positive.code:     this.textScaleFactor,
      this.maxLines,
      this.semanticsLabel,
    }) : assert(textSpan != null),
         data = null,
         super(key: key);
  
  
negative.code:     this.textScaleFactor,
      this.maxLines,
      this.semanticsLabel,
    }) : assert(
           data != null,
           'A non-null String must be provided to a Text widget.',
         ),
         textSpan = null,
         super(key: key);
  
    /// Creates a text widget with a [TextSpan].
    ///
    /// The [textSpan] parameter must not be null.
    const Text.rich(this.textSpan, {
      Key key,
      this.style,
  