pub fn marks(diagnostics: &Diagnostics) -> Vec<Mark>Expand description
Diagnostics as an editor draws them, for a caller that has the diagnostics and not an
Editor — the playground’s analysis has already compiled the text and is not going to do it
twice.
A zero-width span is widened to one character: a caret with nothing under it is a squiggle nobody can see, and “the compiler pointed at the end of the file” is a thing that happens.