Editor story is a bit rough still. I'm using scry (the Crystal Language Server) with coc-nvim. It seems to be a little bit smarter than simple "words in buffer" completion, but not much. Sometimes it just quits and I haven't investigated why. Currently I'm just writing spec tests and simple data structures/algorithms. (the typical thing I do when learning a language) I did start a Lucky project this past weekend to see what that's all about. If I get more into it, I'll probably break down and figure out how to fix autocompletion/go-to-definition/show-references/etc.

I used Crystal with VS code, I don't remember the autocomplete issues, but I'm not a big consumer of that functionality. Syntax highlighting (and I think formatting) were supported with the plugin I used, which was good enough for my purposes.

Yeah, Scry definitely needs some love -- it doesn't really autocomplete outside of local var names and some basic syntactic structures.