@fasterthanlime Not just ship their own parser, but also a greedy parser at that. Want to look at a function signature? Better parse its body down to the last tiny statement!
Venial (https://github.com/PoignardAzur/venial) at least got that particular part right, but it's a hard sell basically because nobody's using it and is still lacking features.
The whole thing is just a bit sad IMO. There's not even that many people who understand proc macros or learning materials to teach them.