trait_alias
The tracking issue for this feature is: #41517
The trait_alias
feature adds support for trait aliases. These allow aliases
to be created for one or more traits (currently just a single regular trait plus
any number of auto-traits), and used wherever traits would normally be used as
either bounds or trait objects.
#![feature(trait_alias)]
trait Foo = std::fmt::Debug + Send;
trait Bar = Foo + Sync;
// Use trait alias as bound on type parameter.
fn foo<T: Foo>(v: &T) {
println!("{:?}", v);
}
pub fn main() {
foo(&1);
// Use trait alias for trait objects.
let a: &Bar = &123;
println!("{:?}", a);
let b = Box::new(456) as Box<dyn Foo>;
println!("{:?}", b);
}