#set text(fallback: false)
\u{1234}

gives a tofu

Oh wait, i might have confused the default font with no fonts (i.e., the thing this PR disallows). But still, I'm unsure what happens when no font in the fallback chain has a .notdef glyph.

IIRC OpenType fonts must always have a notdef glyph (though it may have empty outlines)

Then I suppose it's fine to leave the documentation as it was before

I wonder if #set text(font: ()) could actually be useful in an environment without fonts? E.g. using Typst to draw shapes without any text.

Maybe it could be changed to bail if there's any text, rather than bailing on the set rule itself.

If there's no text, the set text wouldn't really have an effect, right? But what is kinda missing from the PR is at least one sentence motivating this change so that we are all on the same page on what the intent is.

It's true that I should have given a motivation in my original comment, sorry for that.

I feel like specifying an empty font list is significantly more likely to be a mistake than not: If you have text in your document, why would you want to have an empty font list? And if you don't, why would you want to change a property that affects only text?

I tend to agree, though I wonder whether a warning would be a better or worse choice.

The advantage of an error is that the font list is now guaranteed to be non-empty, which I suppose may be useful for some packages (although I don't have any specific example).

Thanks!