I think the comment preceding that should go along with that quote:
https://www.reddit.com/r/rust/comments/1k721w1/comment/moumd91/:
With Bevy clearly being an extended test suite for Rust's trait solver, how did you get the idea to also turn it into a game engine?
https://www.reddit.com/r/rust/comments/1k721w1/comment/mouzde0/:
Every sufficiently advanced test is indistinguishable from a game engine
