NOTE: By "compose" I mean that if I want feature A, B and C from lang X (has A and B), Y (has B and C) and Z (has A and C), but there is no way to get A, B and C in one language without creating a brand new one. I cannot mix and match features from different languages.
(me not knowing might be the ignorant bliss that allows me to just do productive things in them regardless)
Edit: I understand from the updated comment
I've long accepted that no one language can offer all of the language features I'd want, but I also question if I'd even want that language if I got it
(When are we getting a low latency collector in the CLR? But I digress...)
Rust + (garbage collector)
Swift + (cross platform support)
Kotlin + (proper pattern matching)
Unfortunately, none quite hit that central sweet spot, IMO