//@ edition: 2021 #![feature(unsized_locals)] //~^ WARN the feature `unsized_locals` is incomplete async fn f() {} async fn g(x: Box) { let _x = *x; //~^ ERROR the size for values of type `dyn std::fmt::Display` cannot be known at compilation time f().await; } fn main() { let _a = g(Box::new(5)); }