Nim too, as it can use Zig as a compiler.

There's also https://github.com/treeform/shady to compile Nim to GLSL.

Also, more generally, there's an LLVM-IR->SPIR-V compiler that you can use for any language that has an LLVM back end (Nim has nlvm, for example): https://github.com/KhronosGroup/SPIRV-LLVM-Translator

That's not to say this project isn't cool, though. As usual with Rust projects, it's a bit breathy with hype (eg "sophisticated conditional compilation patterns" for cfg(feature)), but it seems well developed, focused, and most importantly, well documented.

It also shows some positive signs of being dog-fooded, and the author(s) clearly intend to use it.

Unifying GPU back ends is a noble goal, and I wish the author(s) luck.