anchor.diff:  /// pass a [GlobalKey] to the constructor and use [GlobalKey.currentState] to
   /// save or reset the form field.
   ///
  +/// For a documentation about the various parameters, see [TextField].
  +///
   /// See also:
   ///
   ///  * <https://material.google.com/components/text-fields.html>
  
positive.code:         autofocus: autofocus,
          obscureText: obscureText,
          maxLines: maxLines,
          onChanged: (String value) {
            field.onChanged(value);
          },
        );
      },
    );
  
negative.code: ///  * [InputDecorator], which shows the labels and other visual elements that
  ///    surround the actual text editing widget.
  class TextFormField extends FormField<String> {
    /// Creates a [FormField] that contains a [TextField].
    ///
    /// For a documentation about the various parameters, see [TextField].
    TextFormField({
      Key key,
      TextEditingController controller,
  