Auto merge of #34232 - ollie27:rustdoc_inline, r=alexcrichton

rustdoc: Don't inline #[doc(hidden)] pub use

Currently if a `#[doc(hidden)] pub use` item is inlined the `hidden`
attribute is ignored so the item can appear in the docs. By never inlining
such imports, they can be stripped.

An example in `std` is [`__OsLocalKeyInner`](https://doc.rust-lang.org/nightly/std/thread/struct.__OsLocalKeyInner.html) which clearly should not be documented.

src/librustdoc/clean/mod.rs

@@ -2389,9 +2389,11 @@ impl Clean<Vec<Item>> for doctree::Import {
         // We consider inlining the documentation of `pub use` statements, but we
         // forcefully don't inline if this is not public or if the
         // #[doc(no_inline)] attribute is present.
+        // Don't inline doc(hidden) imports so they can be stripped at a later stage.
         let denied = self.vis != hir::Public || self.attrs.iter().any(|a| {
             &a.name()[..] == "doc" && match a.meta_item_list() {
-                Some(l) => attr::contains_name(l, "no_inline"),
+                Some(l) => attr::contains_name(l, "no_inline") ||
+                           attr::contains_name(l, "hidden"),
                 None => false,
             }
         });

src/librustdoc/visit_ast.rs

@@ -245,7 +245,9 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         let def_did = def.def_id();
 
         let use_attrs = tcx.map.attrs(id).clean(self.cx);
-        let is_no_inline = use_attrs.list("doc").has_word("no_inline");
+        // Don't inline doc(hidden) imports so they can be stripped at a later stage.
+        let is_no_inline = use_attrs.list("doc").has_word("no_inline") ||
+                           use_attrs.list("doc").has_word("hidden");
 
         // For cross-crate impl inlining we need to know whether items are
         // reachable in documentation - a previously nonreachable item can be

src/test/rustdoc/inline_cross/hidden-use.rs

@@ -0,0 +1,22 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:rustdoc-hidden.rs
+// build-aux-docs
+// ignore-cross-compile
+
+extern crate rustdoc_hidden;
+
+// @has hidden_use/index.html
+// @!has - 'rustdoc_hidden'
+// @!has - 'Bar'
+// @!has hidden_use/struct.Bar.html
+#[doc(hidden)]
+pub use rustdoc_hidden::Bar;

src/test/rustdoc/inline_local/hidden-use.rs

@@ -0,0 +1,20 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+mod private {
+    pub struct Foo {}
+}
+
+// @has hidden_use/index.html
+// @!has - 'private'
+// @!has - 'Foo'
+// @!has hidden_use/struct.Foo.html
+#[doc(hidden)]
+pub use private::Foo;