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diagnostics: span_note/span_help/etc should work with dummy spans #55669
Description
span_note and friends require this non-obvious pattern to work correctly:
if span.is_dummy() {
err.note(msg);
} else {
err.span_note(span, msg);
}If dummy span is passed to span_note then the message simply won't be displayed, but with note it will be attached to the primary err message.
The difference is that note turns into an empty multi-span, but span_note turns into multi-span containing a single dummy span.
I think span_note should "just work" with dummy spans and display the message equivalently to note.
Activity
petrochenkov commentedon Nov 4, 2018
cc @estebank
eddyb commentedon Nov 4, 2018
cc @nikomatsakis @nrc
estebank commentedon Nov 4, 2018
Now multispans also have an
is_dummy()method, so that won't be a source of problems. The only thing that I can think of that could present a challenge is for suggestions (which I guess are out of scope for this thicket) they usually have a fallback with tweaked wording to work asnote/help.I can write out mentoring notes for this.