Column inside ClipRect

main.dart

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 200,
      child: ClipRect(
        clipper: RectClipper(),
        child: Container(
          width: 10000,
          child: Column(children: [
            Text(
                'This line is longer than 200 units and should simply be clipped, not wrapped, using the 10000 units allocated by its parent cointainer. Note that instead of a text widget, where this could be achieved with maxLines and overflow, the behavior should work on an arbitrary widget that does not have these properties.'),
          ]),
        ),
      ),
    );
  }
}

class RectClipper extends CustomClipper<Rect> {
  @override
  Rect getClip(Size size) {
    return Rect.fromLTRB(0, 0, size.width, size.height);
  }

  @override
  bool shouldReclip(covariant CustomClipper<Rect> oldClipper) {
    return true;
  }
}