I spoke to Matz at Euruko 2019 a couple days ago and he mentioned that Ruby 2.7 will ship improved IRB support. Specifically, multiline input. It looks like this is done by introducing a brand new library that replaces Readline called Reline:

• https://github.com/ruby/reline
• https://www.youtube.com/watch?v=8l1ep4nN_KQ

a compatibility library with "readline" stdlib by pure Ruby and works correctly without GNU Readline and works on Windows too.

Pry should support this library as well (and maybe even default to it if it's stable).