Auto merge of #36270 - petrochenkov:pipwarnagain, r=nikomatsakis

Make `private_in_public` compatibility lint warn-by-default again

More details: https://internals.rust-lang.org/t/regression-report-stable-2016-08-16-vs-beta-2016-08-26/3930/10

r? @nikomatsakis

src/test/compile-fail/issue-28514.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![deny(private_in_public)]
+
 pub use inner::C;
 
 mod inner {

src/test/compile-fail/issue-30079.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![deny(private_in_public)]
 #![allow(unused)]
 
 struct SemiPriv;

src/test/compile-fail/private-in-public-warn.rs

@@ -13,8 +13,8 @@
 
 #![feature(associated_consts)]
 #![feature(associated_type_defaults)]
-#![allow(dead_code)]
-#![allow(unused_variables)]
+#![deny(private_in_public)]
+#![allow(unused)]
 #![allow(improper_ctypes)]
 
 mod types {

src/test/compile-fail/private-variant-and-crate-reexport.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![deny(private_in_public)]
 #![allow(dead_code)]
 
 extern crate core;