Enum variants can't be imported via type alias

[pitdicker]

In chrono 0.4.36 we renamed a LocalResult enum to MappedLocalTime, and added a type alias with the name LocalResult.
This turned out to be a breaking change because enum variants can't be imported through a type alias.

enum MappedLocalTime {
    Single,
    Ambiguous,
    None,
}

type LocalResult = MappedLocalTime;

use LocalResult::*;

Gives the error:

    Checking alias v0.1.0 (C:\Users\dicke\Documents\alias)
error[E0432]: unresolved import `LocalResult`
 --> src\main.rs:9:5
  |
9 | use LocalResult::*; // fails
  |     ^^^^^^^^^^^ `LocalResult` is a type alias, not a module

For more information about this error, try `rustc --explain E0432`.
error: could not compile `alias` (bin "alias") due to previous error

I expected the type alias to behave identical to the enum.

Maybe related to RFC 2338 Type alias enum variants.

[djc]

I expected the type alias to behave identical to the enum.

Maybe related to RFC 2338 Type alias enum variants.

As the author of that RFC, I would also have expected this, but of course the RFC doesn't specify explicitly. Tracking issue: #49683.

[cuviper]

If the type alias sets generic parameters, should that carry through?

use std::result::Result::Err;

// We need full args for `Result<T, E>`
return Err::<i32, &str>(...);

use std::io::Result::Err;

// Since `io::Result<T>` already sets `E = io::Error`, do we only need `T`?
return Err::<i32>(...);