Rust: What is the difference between trait aliases and type aliases?

1type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
2
3fn do_something() -> Result<()> {
4    Ok(())
5}

1#![feature(trait_alias)]
2
3trait MyTrait = Send + Sync + 'static;
4
5fn spawn<T: MyTrait>(t: T) {
6    // ...
7}

1trait MyTrait: Send + Sync + 'static {}
2impl<T: Send + Sync + 'static> MyTrait for T {}