The buzzword of the 2015 edition of Rust was stability because version 1.0 promised to be compatible with the versions that followed.
The buzzword of the 2018 edition of Rust was productivity because version 1.31 offered a mature ecosystem of tools that allowed command-line developers for desktop operating systems (Linux, Windows, macOS) to be more productive.
There is an intent to have a new Rust edition in the coming years, but for this edition, neither its release date, nor its features, nor its buzzword is defined yet.
However, after the release of the 2018 edition, several needs of Rust developers are being targeted by Rust ecosystem developers around the world. It is probable that the new buzzword will come out of ...