Have you seen AssemblyScript, Poetry, Walt, and Speedy:

https://github.com/AssemblyScript/assemblyscript

https://github.com/FantasyInternet/poetry

https://github.com/ballercat/walt

https://github.com/MichaReiser/speedy.js

Unlike Rust, which has excellent support for wasm output but wasn't created with wasm in mind, the above languages appear to have been created specifically with wasm as the native compile target.

Also, there's an excellent curated list of languages that compile to wasm:

https://github.com/appcypher/awesome-wasm-langs