Getting a weird error message in Mix i've not see before. "Because your app depends on XXX empty"

This was seen on IRC yesterday also, pasting the relevant logs:

10:47:42 <Nicd> I was suspicious of that error message but it’s literally what you said :smiley: https://usercontent.irccloud-cdn.com/file/G9t4aRmi/Screenshot%202023-03-09%20at%2010.47.17.png

10:48:13 <josevalim> Nicd: this is a bug in the hex resolver, i will investigate

10:54:04 <josevalim> here is a minimal example that reproduces the phoenix empty bug:

10:54:07 <josevalim> Snippet | IRCCloud

10:55:58 <josevalim> serafeim: i know what is happening. the scrivener_html does not allow phoenix 1.7. so there is an error but the error message is unclear

So I guess there are conflicting package requirements (some other package doesn’t allow that version of rustler or httpoison), but the error message is bugged.