Kotlin has been picking up steam lately:
We’ve seen over 160’000 people using it during the last year. OSS projects on Github grew from 2.4M to 10M lines of Kotlin code (about 4x). Our Slack community has grown from 1’400 to over 5’700 people (over 4x).
Many well-known companies are using Kotlin: Pinterest, Coursera, Netflix, Uber, Square, Trello, Basecamp, amongst others. Corda, a distributed ledger developed by a consortium of well-known banks (such as Goldman Sachs, Wells Fargo, J.P. Morgan, Deutsche Bank, UBS, HSBC, BNP Paribas, Société Générale), has over 90% Kotlin in its codebase.
https://blog.jetbrains.com/kotlin/2017/03/kotlin-1-1/
We'd love to see this supported on Phabricator!