rust - What is the difference between using a type as a different name and a type alias? -

what difference between

use hyper::status::statuscode error; 

and

type error = hyper::status::statuscode; 

are more differences between them except type can pub type? benefits between using 1 or another?

in case of simple types, in example, there doesn't seem semantic difference. moreover, there direct analogue use pub type, it's pub use:

// available other modules pub use hyper::status::statuscode error; 

however, there differences in more complex cases. example, can define generic type aliases or aliases specialized generic types:

type result<t> = ::std::result::result<t, myerror>;  type optioni32 = option<i32>; 

the general idea use type aliases because more powerful , suggest intent more clearly, result, , use use .. .. when want import specific name conflicts in current namespace:

use std::io::read stdread;  trait read: stdread { ... } 

note using path-qualified identifiers should preferred use renaming. above better written as

use std::io;  trait read: io::read { ... } 

(unless read methods used concrete type in same file, of course).

using use .. .. substitute type (in case possible) uncommon , think should avoided.