#![feature(generator_trait)] #![feature(generators)] #![feature(unsized_locals)] //~^ WARN the feature `unsized_locals` is incomplete and may not be safe to use and/or cause compiler crashes use std::ops::Generator; fn across() -> impl Generator { move || { let b: [u8] = *(Box::new([]) as Box<[u8]>); //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time yield; for elem in b.iter() {} } } fn main() { across(); }