extern crate fails doc tests

[Osspial]

If a doc test attempts to import any types declared in it's own crate, including the phrase extern crate anywhere in the code will cause the test to not compile, throwing a "unresolved import" error at the attempted import. For example, if we have struct Foo in crate bar, with the crate baz declared under dev_dependencies, these tests will all fail to compile

/// ```
/// extern crate baz;
/// use bar::Foo;
/// ```
pub struct Foo{}

/// ```
/// // The phrase "extern crate" breaks this!
/// use bar::Foo;
/// ```
pub struct Foo{}

/// ```
/// use bar::Foo;
/// let string = "extern crate";
/// ```
pub struct Foo{}

The following error log is given by cargo test:

running 1 test
test Foo_0 ... FAILED

failures:

---- Foo_0 stdout ----
        <anon>:2:9: 2:12 error: unresolved import `bar::Foo`. Maybe a missing `extern crate bar`? [E0432]
<anon>:2     use bar::Foo;
                 ^~~
error: aborting due to previous error(s)
thread 'Foo_0' panicked at 'Box<Any>', ../src/librustc\session/mod.rs:153
stack backtrace:
   0:         0x61cc34dc - strncmp
   1:         0x61cc2b5c - strncmp
   2:         0x61c84d6f - strncmp
   3:         0x67f193ba - strncmp
   4:         0x67f96c9b - strncmp
   5:         0x6ca6943d - strncmp
   6:         0x6ca6e301 - strncmp
   7:         0x661e3803 - strncmp
   8:         0x61caf9ba - strncmp
   9:         0x661e3bba - strncmp
  10:         0x61cc1209 - strncmp
  11:     0x7fff457f8101 - strncmp


failures:
    Foo_0

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured

[alexcrichton]

Thanks for the report! I think this is actually an upstream rustdoc bug, could you open an issue there instead?

[Osspial]

Sure. It's re-submitted here.

[alexcrichton]

Thanks!