Error when adding AppBar, tutorial code suddenly not matching previous step.

[Sidewinder1138]

Page URL

https://docs.flutter.dev/learn/pathway/tutorial/layout

Page source

https://github.com/flutter/website/blob/main/sites/docs/src/content/learn/pathway/tutorial/layout.md

Describe the problem

In the previous step of this tutorial (3) we added a little Tile StatelessWidget. There was also no existing AppBar.
In this step, suddenly we are back to "Hello World".
Also, when I go to add the AppBar, I get an error about "The constructor being called isn't a const constructor."
This is pretty jarring/confusing for beginners. Probably an easy fix, but I don't know enough to contribute yet.

Expected fix

As you go through the steps of the tutorial, things shouldn't suddenly change on you!
If this is a common "gotcha" regarding const, please add a box explaining how to resolve it.

Additional context

No response

I would like to fix this problem.

• I will try and fix this problem on docs.flutter.dev.

[Sidewinder1138]

I tried copying and pasting code from the tutorial to overwrite what was in my local code, and that worked. But I can't see what changes are relevant to that annoying const error.

Normally I would blame a typo on my part, but the problem is that the tutorial is disjoint, suddenly changes things without explaining each change.

[harshyadavDeveloper]

@Sidewinder1138 I think what you’re seeing is mostly caused by how the tutorial steps are structured rather than a broken example.

Each step in the tutorial represents a snapshot of the app at that stage, so sometimes code from earlier steps is replaced or reorganized without explicitly showing every intermediate change. That can definitely feel jarring for beginners.

The const constructor error is also likely related to leftover const keywords after introducing non-const values or runtime state. Since copying the tutorial code directly resolved the issue, the example itself seems correct, but the transition between steps could probably be explained more clearly in the tutorial.