Attributes not documented in the Rust Reference

[jimmycuadra]

I have discovered a few attributes that are not documented in the Rust Reference:

• cfg_attr
• stable
• unstable
• deprecated

The ones relating to stability are also not mentioned in the Rust Book in the Documentation section.

[steveklabnik]

The ones relating to stability are also not mentioned in the Rust Book in the Documentation section.

Yeah, that section is mostly about documenting your own code, and these attributes cannot be used outside of the standard library.

[jimmycuadra]

I didn't realize they were specific to the stdlib. That would explain why they didn't work when I tried them. What's the reason for limiting to the stdlib? It'd be a very useful feature in general.

[steveklabnik]

They're closely tied to release channels, which non-stdlib crates don't use. We agree it would be useful and want to make something, but haven't worked on a design yet.