Const list has non-const items. Why?

Question

I'm creating a test with const Widget list.

const passing = [
 Item(),
 Item(),
];

But test fails. I found out that items are non const! Their hashCodes are different as if they are (new). Why?

enter image description here

enter image description here

Reproducing

import 'package:flutter/material.dart';
import 'package:test/test.dart';
void main() {
 test('Non equal consts', () {
 final one = constList[0];
 final another = constList[1];
 expect(one, another);
 });
}
const constList = [
 ConstItem(),
 ConstItem(),
];
class ConstItem extends Widget {
 const ConstItem({Key? key}) : super(key: key);
 @override
 Element createElement() {
 throw UnimplementedError();
 }
}

enter image description here

• hacker1024: Are you sure your reproduction is accurate? one and another have equal hashCode values in DartPad.
• jamesdlin: It's not that this const List has non-const elements; the elements surely are immutable. What you're observing is that the elements are not canonicalized. I can reproduce this when I run it locally, and it seems to be tied to ConstItem deriving from Widget.
• jamesdlin: I would recommend filing an issue.
• cheiser: @hacker1024 It is correct sample. I have edited the post and provided image with proof
• jamesdlin: Closing the loop: OP filed github.com/flutter/flutter/issues/107767, where it was explained that it's normal for debug builds: docs.flutter.dev/testing/…