Stability checker doesn't recurse down reexports properly

[Manishearth]

stability.rs:

#![crate_type="lib"]
#![feature(staged_api)]

#![staged_api]
#![stable(feature = "stability", since = "1.0.0")]

mod foo {
   #[derive(Copy)]
   pub struct Bar;
}

#[unstable(feature="foobar")]
pub mod foobar {
    pub use super::foo::*;
}

test.rs:

extern crate stability;
use stability::foobar::Bar;

fn main(){
   let x = Bar; //~ ERROR use of unmarked library feature
}

#[unstable] is inherited through mods (only #[stable] isn't inherited). However, in this particular case, the inheritance doesn't cross the reexport.

A more concrete example is the hash_state module. Chris fixed the stability of its items in this PR, however the module itself was private and reexported as an #[unstable] module before the PR. Yet, usage of items within the hash_state module were broken before the PR.

This seems wrong, #[unstable] (and the others, except #[stable]) should be inherited down pub uses.

cc @brson

[steveklabnik]

Traige: staged_api is now only available to the compiler, so I was unable to come up with a quick test case.

[petrochenkov]

Still an issue.
(Also, staged_api is still available to everyone on unstable, it just uses misleading error message to hide the truth.)

[steveklabnik]

Ahhh I thought I was using unstable, I guess I wasn't.

On Mar 4, 2016, 12:03 -0500, Vadim Petrochenkovnotifications@github.com, wrote:

Still an issue.
(Also,staged_apiis still available to everyone on unstable, it just uses misleading error message to hide the truth.)

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[steveklabnik]

Triage: not aware of any changes at all here. There's not a ton of pressure to fix this.