rustdoc: Only hide possibly private modules

If an empty public module has no documentation, it shouldn't emit a page that's
just a redirect loop to itself!

Closes #16265

src/librustdoc/html/render.rs

@@ -1352,7 +1352,9 @@ impl Context {
     fn ignore_private_item(&self, it: &clean::Item) -> bool {
         match it.inner {
             clean::ModuleItem(ref m) => {
-                (m.items.len() == 0 && it.doc_value().is_none()) ||
+                (m.items.len() == 0 &&
+                 it.doc_value().is_none() &&
+                 it.visibility != Some(ast::Public)) ||
                 (self.passes.contains("strip-private") && it.visibility != Some(ast::Public))
             }
             clean::PrimitiveItem(..) => it.visibility != Some(ast::Public),

src/test/rustdoc/issue-16265-1.rs

@@ -0,0 +1,18 @@
+// Copyright 2015 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.
+
+pub struct Foo;
+
+// @has issue_16265_1/traits/index.html '[src]'
+pub mod traits {
+    impl PartialEq for super::Foo {
+        fn eq(&self, _: &super::Foo) -> bool { true }
+    }
+}

src/test/rustdoc/issue-16265-2.rs

@@ -0,0 +1,15 @@
+// Copyright 2015 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.
+
+
+// @has issue_16265_2/index.html '[src]'
+
+trait Y {}
+impl Y for Option<u32>{}