Variant of detail_page.dart that uses several hypothetical features of Dart to reduce verbosity

detail_page.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart' show Divider;
import 'package:landmarks/widgets/favorite_button.dart';

import '../model/landmarks_model.dart';
import '../model/landmark.dart';
import '../widgets/circle_image.dart';
import '../widgets/map_view.dart';

extension on BuildContext {
  TextStyle textStyleWith({color in CupertinoColors, ...}) ==>
      CupertinoTheme.of(this).textTheme.textStyle.copyWith;
}

class DetailPage extends StatelessWidget {
  final Landmark landmark;

  const DetailPage({super.key, this.landmark});

  override build(context) {
    return CupertinoPageScaffold(
      navigationBar: CupertinoNavigationBar(
        middle: Text(landmark.name),
        previousPageTitle: 'Landmarks',
      ),
      SingleChildScrollView(
        Column(
          [
            Stack(
              alignment: .topStart,
              [
                MapView(height: 300, coordinates: landmark.coordinates),
                Padding(
                  padding: const .fromLTRB(0, 170, 0, 0),
                  Center(CircleImage(image: landmark.image)),
                ),
              ],
            ),
            Padding(
              padding: const .all(16),
              Column(
                mainAxisSize: .min,
                crossAxisAlignment: .start,
                [
                  Row(
                    [
                      Text(landmark.name,
                          style: context.textStyleWith(fontSize: 25)),
                      Padding(
                        padding: const .symmetric(horizontal: 10),
                        FavoriteButton(
                          isSet: landmark.isFavorite,
                          onTap: () {
                            LandmarksModel.of(context).updateLandmark(
                                landmark.id,
                                landmark.copyWith(
                                    isFavorite: !landmark.isFavorite));
                          },
                        ),
                      )
                    ],
                  ),
                  Row(
                    [
                      Text(landmark.park,
                          style: context.textStyleWith(
                              fontSize: 15, color: .systemGrey)),
                      const Spacer(),
                      Text(landmark.state,
                          style: context.textStyleWith(
                              fontSize: 15, color: .systemGrey)),
                    ],
                  ),
                  const Divider(),
                  Text('About ${landmark.name}',
                      style: context.textStyleWith(fontSize: 22)),
                  Flexible(
                    Text(landmark.description,
                        style: context.textStyleWith(fontSize: 17)),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

Assumed hypothetical language features used in this example:

• Forwarding functions, github.com/dart-lang/language/issues/3444,
  needed for textStyleWith.

• Parameter default scopes, github.com/dart-lang/language/issues/3834,
  needed to allow .systemGrey rather than CupertinoColors.systemGrey.
  Also needed to similarly omit other scope names.
  AlignmentDirectional.topStart: Many ways to do this.
  EdgeInsets.fromLTRB: Can use static extension and default scope.
  EdgeInsets.all, EdgeInsets.symmetric: Similar.
  MainAxisSize.min, CrossAxisAlignment.start: Trivial.

• Inferred required,
  https://com/dart-lang/language/blob/main/working/0015-infer-required/feature-specification.md,
  needed to omit required in constructor.

• Optionally named parameters, github.com/dart-lang/language/issues/831,
  needed in order to omit child: and children: (other proposals could do this, too).