You're replying to Steve Klabnik, co-author of the Rust book [0] and (previously) a core team member for years. If he says it's been used on big projects I'd be inclined to believe him.
Note that it's likely that some of the biggest applications aren't public and so even if identified you couldn't actually count the lines yourself.
Note that it's likely that some of the biggest applications aren't public and so even if identified you couldn't actually count the lines yourself.
[0] https://doc.rust-lang.org/stable/book/