[2.0.66] Crash when mod changes "clicked_font_color" on label (Color:toAguiColor)

[MerryDreambound]

What did you do?
Context:
I'm creating a mod to organize space platforms, and I'm trying to recreate the "Surfaces" GUI, to do so I tried to change the "clicked_font_color" style of a label (Important because it shouldn't be possible) Factorio API reference

Repro steps:
Download/Install the mod "UntitledGuiGuideTemplate-Merry" in the attachments
Open factorio
Create a new sandbox world (Click yes to all boxes that appears when you appear in the world)
Create a new space platform (Fully)
Open the custom GUI from the mod with "CONTROL + i"
It segfaults

What happened?
It segfaults/crashes factorio

What did you expect to happen instead?
For factorio to give out the following Notice
"The mod X caused a non-recoverable error.
Please report this error to the mod author."
and to drop the user in the main menu.

Does it happen always, once, or sometimes?
It happens always

[Rseding91]

Thanks for the report. This is now fixed for the next release. The lua docs should now say that it's possible to write that value on labels and it will no longer crash.