Revert "Remove unnecessary trait accessibility check."

This reverts commit f4f95eb3a9.

src/test/run-pass/issue-16264.rs

@@ -1,27 +0,0 @@
-// 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.
-
-use outer::Foo;
-
-mod outer {
-    pub use self::inner::Foo;
-
-    mod inner {
-        pub trait Foo {
-            fn bar(&self) {}
-        }
-        impl Foo for i32 {}
-    }
-}
-
-fn main() {
-    let x: i32 = 0;
-    x.bar();
-}