It appears to not be a reserved word at all: $ echo 'fn main() { let do = 1; }' | rustc - runs with just an unused variable warning (if it were reserved it

It appears to not be a reserved word at all: $ echo 'fn main() { let do = 1; }' | rustc - runs with just an unused variable warning (if it were reserved it would fail with "error: `do` is a reserved keyword").