issue 114952

main.dart

import 'package:flutter/material.dart';

void main() => runApp(
      const MaterialApp(
        home: MyScaffold(
          tabs: [
            MyColumn(),
            MyStack(),
            MyPositonedBottom(),
            MyPositonedTop(),
          ],
        ),
      ),
    );

abstract class TabWidget extends StatelessWidget {
  final Widget tab;
  const TabWidget({super.key, required this.tab});
}

class MyScaffold extends StatelessWidget {
  final List<TabWidget> tabs;
  const MyScaffold({
    super.key,
    this.tabs = const [],
  });

  @override
  Widget build(context) => DefaultTabController(
        length: tabs.length,
        child: Scaffold(
            appBar: AppBar(
              title: TabBar(
                tabs: [for (final tabWidget in tabs) tabWidget.tab],
              ),
            ),
            body: TabBarView(children: tabs)),
      );
}

class MyColumn extends TabWidget {
  const MyColumn({
    super.key,
    super.tab = const Text('column'),
  });

  @override
  Widget build(context) => Column(
        children: const [
          MyTextField(),
        ],
      );
}

class MyStack extends TabWidget {
  const MyStack({
    super.key,
    super.tab = const Text('stack'),
  });

  @override
  Widget build(context) => Stack(
        alignment: Alignment.center,
        children: const [
          MyTextField(),
        ],
      );
}

class MyPositonedBottom extends TabWidget {
  const MyPositonedBottom({
    super.key,
    super.tab = const Text('positioned bottom'),
  });

  @override
  Widget build(context) => Stack(
        children: [
          Positioned(
            width: MediaQuery.of(context).size.width,
            bottom: MediaQuery.of(context).size.height * .5,
            child: const MyTextField(),
          ),
        ],
      );
}

class MyPositonedTop extends TabWidget {
  const MyPositonedTop({
    super.key,
    super.tab = const Text('positioned top'),
  });

  @override
  Widget build(context) => Stack(
        children: [
          Positioned(
            width: MediaQuery.of(context).size.width,
            top: MediaQuery.of(context).size.height * .5,
            child: const MyTextField(),
          ),
        ],
      );
}

class MyTextField extends StatelessWidget {
  const MyTextField({super.key});

  @override
  Widget build(context) => Form(
        autovalidateMode: AutovalidateMode.always,
        child: Container(
          color: Colors.yellow.withOpacity(.3),
          child: Padding(
            padding: const EdgeInsets.all(10),
            child: TextFormField(
              decoration: const InputDecoration(
                border: OutlineInputBorder(
                  borderSide: BorderSide(
                    width: 1,
                    color: Colors.black,
                  ),
                ),
              ),
              validator: (value) => 'warning',
            ),
          ),
        ),
      );
}