Use of unicode_internals points people to issue #0

[alex]

There is no issue #0 :-) I'm guessing someone intended #0 to mean "we don't have an issue for this", but either the error message emitting machinery needs to suppress it, or it should be given a real error message. Here's what it looks like:

error[E0658]: use of unstable library feature 'unicode_internals' (see issue #0)
  --> /home/travis/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-syntax-94.0.0/parse/lexer/mod.rs:18:5
   |
18 | use std_unicode::property::Pattern_White_Space;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add #![feature(unicode_internals)] to the crate attributes to enable
error[E0658]: use of unstable library feature 'unicode_internals' (see issue #0)
    --> /home/travis/.cargo/registry/src/github.com-1ecc6299db9ec823/rustc-ap-syntax-94.0.0/parse/lexer/mod.rs:1725:21
     |
1725 |     c.map_or(false, Pattern_White_Space)
     |                     ^^^^^^^^^^^^^^^^^^^
     |
     = help: add #![feature(unicode_internals)] to the crate attributes to enable
error: aborting due to 2 previous errors

You can see it here: https://travis-ci.org/alex/ct-tools/builds/366818424