Quoting: https://tech.lgbt/@wakame/116313296965649089

cc @wakame

That's something I plan to implement into #Kittyscript. It will be a dynamic language at heart, but allow annotating types and other constraints, and also inferring them at compile-time.

@LunaDragofelis
Contraints, BDSM style: You can add them if you like, but it requires consent.

The "consent" part seems to be missing in a lot of programming languages, it's more like "if you want to use this language, you have to live by our rules. Period."