I'm happy to announce we improved support for Rust in CoCalc, an online platform for collaborative calculation. The stable, beta and nightly channels are available out of the box: software update 2019-11-19.
~$ rustc --version
rustc 1.39.0 (4560ea788 2019-11-04)
~$ rustc +beta --version
rustc 1.40.0-beta.2 (2a0ba54fa 2019-11-16)
~$ rustc +nightly --version
rustc 1.41.0-nightly (5c5b8afd8 2019-11-16)
Editing code files in the frame editor supports code formatting via rustfmt as well.
