As others have mentioned,
Rust is likely to be the next big game dev language, if there ever is one. It, uniquely among programming languages, offers memory safety without garbage collection, and produces code as efficient as C++. Rust is also great for writing multi-threaded code, since it can statically prevent data races. It's also very expressive, and borrows a lot of cool features from other modern but niche languages.
Rust currently has two problems. First, it's
very new, with version 1.0 just coming out next month. This means that the libraries and documentation available are quite immature. Second, is that the compiler is currently very conservative about its notion of safety. There's a lot of code you can write in Rust that is safe, but the compiler can't
prove is safe, and therefore won't compile. Rust provides an escape hatch that let's you write that code anyway, but then you lose all of the compiler's static safety checking in that block, which makes it pretty dangerous (though, no more dangerous than writing normal C++). This will improve over time as the compiler gets better, and as people developed more skill in the language.
TL;DR Rust is very cool, and it's a good time to check it out if you want in on the ground floor, but it's a few years away from being a serious contender.