pub with macro 2.0 breaks docs

[valff]

Using pub qualifier with declarative macros 2.0 breaks the missing_docs lint for private items, as well as exposes them with rustdoc.

The following code shouldn't produce warnings (playground):

//! ...
#![feature(decl_macro)]
#![warn(missing_docs)]

/// ...
pub mod foo {
  // Try to comment out the macro, and warnings will be disappeared.
  pub macro bar() { println!("bar"); }
  
  #[allow(dead_code)]
  fn baz() {}
}

fn main() {}

rustc --version --verbose:

rustc 1.22.0-nightly (dcbbfb6e8 2017-10-12)
binary: rustc
commit-hash: dcbbfb6e807fdff9c9ba80073bb755f9d9d95e31
commit-date: 2017-10-12
host: x86_64-unknown-linux-gnu
release: 1.22.0-nightly
LLVM version: 4.0

[petrochenkov]

The reason is that everything reachable from a public macro 2.0 is currently very pessimistically marked as reachable from the outer world (this affects linking in the first place, but also lints like missing docs, missing Copy/Debug impls, etc).

The solution could be to mark as reachable only items actually leaked by the macro (this can be hard), or to introduce one more gradation of reachability and suppress lints for it.

[matthewjasper]

This appears to have been fixed by #63114

[workingjubilee]

Appears to still emit warnings in playground as of Now, not fixed?

[beepster4096]

Right now, it works without errors

[valff]

It's fixed now, thanks! The current warning is legitimate and unrelated to the issue.