[Agda] Installing Idris without breaking Agda

[Dave Martin]

I hope this isn't too off topic, but understand that I'm almost completely "computer illiterate" and I don't know of any better place to ask it!

I some time ago installed (Linux Mint 19) Emacs and Agda; they apparently work perfectly. But now I want to install Idris as well. I followed the official instructions ( http://docs.idris-lang.org/en/latest/tutorial/starting.html ). I first installed cabal, then did cabal update, both with no messages; then I finally tried cabal install idris. Whereupon I get this message:

cabal: The following packages are likely to be broken by the reinstalls:
uri-encode-1.5.0.5
Agda-2.5.3
Use --force-reinstalls if you want to install anyway.

Ah, what is going on here? I don't want to break Agda! (Taking the website's suggestion of adding to my PATH didn't help.) How do I handle this puzzle?

Also: Once I succeed, will I be able to use Idris in Emacs like I can Agda? I have used Atom and I find it unpleasant and confusing.

Any help anyone can provide would be appreciated; again, I was sure this small community is as likely as any out there to be familiar with what it takes.