derived_references_self runtime error is not documented

[Keavon]

Describe the problem

After upgrading my project from Svelte 4 to 5, I get a runtime error linking me to https://svelte.dev/docs/svelte/runtime-errors#Client-errors-derived_references_self which contains no description at all, and the error description itself is cryptic and I don't know what to make of it.

Describe the proposed solution

The documentation should explain what this means, when it can occur, and offer a proposed solution.

Importance

i cannot use svelte without it

[Keavon]

I did ultimately manage to whittle down to the problem and solve it. However, the request for filling in this blank documentation would still be helpful to others.

More details in the Svelte Discord's question here: https://discord.com/channels/457912077277855764/1461961640718372905

To summarize the resolution in case anyone else needs it:

This pair of lines is the essence of the problem and the solution for one file and this line for the other file.

The code was previously trying to read from the child component to determine if it's open, then write that value back to the child component, which seems a bit paradoxical now that I think about it, and I guess the Svelte 5 compiler also wasn't happy with it.