rustc: Remove #![unstable] annotation

These are now no longer necessary with `-Z force-unstable-if-unmarked`

src/libarena/lib.rs

@@ -19,7 +19,7 @@
 //! objects of a single type.
 
 #![crate_name = "arena"]
-#![unstable(feature = "rustc_private", issue = "27812")]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -32,7 +32,7 @@
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
 #![feature(generic_param_attrs)]
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![cfg_attr(test, feature(test))]
 
 #![allow(deprecated)]

src/libflate/lib.rs

@@ -15,7 +15,7 @@
 //! [mz]: https://code.google.com/p/miniz/
 
 #![crate_name = "flate"]
-#![unstable(feature = "rustc_private", issue = "27812")]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -25,7 +25,7 @@
 #![deny(warnings)]
 
 #![feature(libc)]
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![feature(unique)]
 #![cfg_attr(test, feature(rand))]
 

src/libfmt_macros/lib.rs

@@ -15,7 +15,7 @@
 //! generated instead.
 
 #![crate_name = "fmt_macros"]
-#![unstable(feature = "rustc_private", issue = "27812")]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -25,7 +25,7 @@
        test(attr(deny(warnings))))]
 #![deny(warnings)]
 
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![feature(unicode)]
 
 pub use self::Piece::*;

src/libgetopts/lib.rs

@@ -78,9 +78,9 @@
 //! ```
 
 #![crate_name = "getopts"]
-#![unstable(feature = "rustc_private",
+#![cfg_attr(stage0, unstable(feature = "rustc_private",
             reason = "use the crates.io `getopts` library instead",
-            issue = "27812")]
+            issue = "27812"))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -91,7 +91,7 @@
 
 #![deny(missing_docs)]
 #![deny(warnings)]
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 
 use self::Name::*;
 use self::HasArg::*;

src/libgraphviz/lib.rs

@@ -284,8 +284,8 @@
 //! * [DOT language](http://www.graphviz.org/doc/info/lang.html)
 
 #![crate_name = "graphviz"]
-#![unstable(feature = "rustc_private", issue = "27812")]
-#![feature(staged_api)]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(staged_api))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",

src/libproc_macro_plugin/lib.rs

@@ -72,7 +72,7 @@
 //! }
 //! ```
 #![crate_name = "proc_macro_plugin"]
-#![unstable(feature = "rustc_private", issue = "27812")]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
 #![feature(plugin_registrar)]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
@@ -81,9 +81,9 @@
        html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
+#![cfg_attr(stage0, feature(rustc_private))]
 
 extern crate rustc_plugin;
 extern crate syntax;

src/librustc/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -36,15 +35,17 @@
 #![feature(nonzero)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
 #![feature(slice_patterns)]
 #![feature(specialization)]
-#![feature(staged_api)]
 #![feature(unboxed_closures)]
 #![feature(discriminant_value)]
 #![feature(sort_unstable)]
 #![feature(trace_macros)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 #![recursion_limit="128"]
 
 extern crate arena;

src/librustc_back/lib.rs

@@ -22,7 +22,6 @@
 //! build speedups.
 
 #![crate_name = "rustc_back"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -34,10 +33,12 @@
 #![feature(const_fn)]
 #![feature(libc)]
 #![feature(rand)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![cfg_attr(test, feature(rand))]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate syntax;
 extern crate libc;
 extern crate serialize;

src/librustc_bitflags/lib.rs

@@ -11,11 +11,11 @@
 
 #![crate_name = "rustc_bitflags"]
 #![feature(associated_consts)]
-#![feature(staged_api)]
 #![crate_type = "rlib"]
 #![no_std]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![deny(warnings)]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 //! A typesafe bitmask flag generator.
 

src/librustc_borrowck/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_borrowck"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -21,10 +20,13 @@
 
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(associated_consts)]
 #![feature(nonzero)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
 extern crate syntax_pos;

src/librustc_const_eval/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_const_eval"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -23,8 +22,6 @@
       html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(slice_patterns)]
 #![feature(box_patterns)]
@@ -32,6 +29,10 @@
 #![feature(const_fn)]
 #![feature(i128_type)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate arena;
 #[macro_use] extern crate syntax;
 #[macro_use] extern crate log;

src/librustc_const_math/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_const_math"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -23,12 +22,14 @@
       html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(const_fn)]
 #![feature(i128)]
 #![feature(i128_type)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate syntax;
 
 extern crate serialize as rustc_serialize; // used by deriving

src/librustc_data_structures/lib.rs

@@ -17,7 +17,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_data_structures"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -28,8 +27,6 @@
 #![feature(shared)]
 #![feature(collections_range)]
 #![feature(nonzero)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(unboxed_closures)]
 #![feature(fn_traits)]
 #![feature(untagged_unions)]
@@ -42,6 +39,10 @@
 #![feature(manually_drop)]
 #![feature(struct_field_attributes)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 #![cfg_attr(unix, feature(libc))]
 #![cfg_attr(test, feature(test))]
 

src/librustc_driver/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_driver"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -28,9 +27,11 @@
 #![feature(libc)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
 #![feature(set_stdio)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 extern crate arena;
 extern crate getopts;

src/librustc_errors/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_errors"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -19,11 +18,13 @@
 
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(range_contains)]
 #![feature(libc)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate term;
 extern crate libc;
 extern crate serialize as rustc_serialize;

src/librustc_incremental/lib.rs

@@ -11,7 +11,6 @@
 //! Support for serializing the dep-graph and reloading it.
 
 #![crate_name = "rustc_incremental"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -19,12 +18,14 @@
       html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(rand)]
 #![feature(conservative_impl_trait)]
 #![feature(sort_unstable)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate graphviz;
 #[macro_use] extern crate rustc;
 extern crate rustc_data_structures;

src/librustc_lint/lib.rs

@@ -20,7 +20,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_lint"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -34,9 +33,11 @@
 #![feature(i128_type)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
 #![feature(slice_patterns)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use]
 extern crate syntax;

src/librustc_llvm/lib.rs

@@ -14,7 +14,6 @@
 #![allow(dead_code)]
 
 #![crate_name = "rustc_llvm"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -27,10 +26,12 @@
 #![feature(concat_idents)]
 #![feature(libc)]
 #![feature(link_args)]
-#![feature(staged_api)]
-#![feature(rustc_private)]
 #![feature(static_nobundle)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate libc;
 #[macro_use]
 #[no_link]

src/librustc_metadata/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_metadata"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -24,10 +23,12 @@
 #![feature(proc_macro_internals)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
 #![feature(specialization)]
-#![feature(staged_api)]
 #![feature(discriminant_value)]
+#![feature(rustc_private)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use]
 extern crate log;

src/librustc_mir/lib.rs

@@ -18,18 +18,19 @@
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![deny(warnings)]
-#![unstable(feature = "rustc_private", issue = "27812")]
 
 #![feature(associated_consts)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(i128_type)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(placement_in_syntax)]
 #![feature(collection_placement)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 #[macro_use] extern crate log;
 extern crate graphviz as dot;
 #[macro_use]

src/librustc_passes/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_passes"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -24,8 +23,10 @@
 #![deny(warnings)]
 
 #![feature(rustc_diagnostic_macros)]
-#![feature(staged_api)]
-#![feature(rustc_private)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use]
 extern crate rustc;

src/librustc_platform_intrinsics/lib.rs

@@ -9,10 +9,10 @@
 // except according to those terms.
 
 #![crate_name = "rustc_platform_intrinsics"]
-#![unstable(feature = "rustc_private", issue = "27812")]
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![deny(warnings)]
 #![allow(bad_style)]
 

src/librustc_plugin/lib.rs

@@ -51,7 +51,6 @@
 //! for more examples.
 
 #![crate_name = "rustc_plugin"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -59,9 +58,11 @@
        html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(staged_api)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use] extern crate syntax;
 

src/librustc_privacy/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_privacy"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -18,8 +17,10 @@
 #![deny(warnings)]
 
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 extern crate rustc;
 #[macro_use] extern crate syntax;

src/librustc_resolve/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_resolve"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -19,8 +18,10 @@
 
 #![feature(associated_consts)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use]
 extern crate log;

src/librustc_save_analysis/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustc_save_analysis"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -19,8 +18,10 @@
 
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use] extern crate rustc;
 

src/librustc_trans/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "rustc_trans"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -33,12 +32,14 @@
 #![feature(libc)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
 #![feature(slice_patterns)]
-#![feature(staged_api)]
 #![feature(unicode)]
 #![feature(conservative_impl_trait)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 use rustc::dep_graph::WorkProduct;
 use syntax_pos::symbol::Symbol;
 

src/librustc_typeck/lib.rs

@@ -64,7 +64,6 @@
 */
 
 #![crate_name = "rustc_typeck"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -81,8 +80,10 @@
 #![feature(never_type)]
 #![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;

src/librustdoc/lib.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 #![crate_name = "rustdoc"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -21,14 +20,16 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(libc)]
-#![feature(rustc_private)]
 #![feature(set_stdio)]
 #![feature(slice_patterns)]
-#![feature(staged_api)]
 #![feature(test)]
 #![feature(unicode)]
 #![feature(vec_remove_item)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate arena;
 extern crate getopts;
 extern crate env_logger;

src/libserialize/lib.rs

@@ -15,9 +15,9 @@
 */
 
 #![crate_name = "serialize"]
-#![unstable(feature = "rustc_private",
+#![cfg_attr(stage0, unstable(feature = "rustc_private",
             reason = "deprecated in favor of rustc-serialize on crates.io",
-            issue = "27812")]
+            issue = "27812"))]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -32,7 +32,7 @@
 #![feature(core_intrinsics)]
 #![feature(i128_type)]
 #![feature(specialization)]
-#![feature(staged_api)]
+#![cfg_attr(stage0, feature(staged_api))]
 #![cfg_attr(test, feature(test))]
 
 extern crate collections;

src/libsyntax/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "syntax"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -24,12 +23,14 @@
        test(attr(deny(warnings))))]
 #![deny(warnings)]
 
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(unicode)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(i128_type)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 extern crate serialize;
 #[macro_use] extern crate log;
 #[macro_use] extern crate bitflags;

src/libsyntax_ext/lib.rs

@@ -11,7 +11,6 @@
 //! Syntax extensions in the Rust compiler.
 
 #![crate_name = "syntax_ext"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -20,8 +19,10 @@
 #![deny(warnings)]
 
 #![feature(proc_macro_internals)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
+
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
 
 extern crate fmt_macros;
 extern crate log;

src/libsyntax_pos/lib.rs

@@ -15,7 +15,6 @@
 //! This API is completely unstable and subject to change.
 
 #![crate_name = "syntax_pos"]
-#![unstable(feature = "rustc_private", issue = "27812")]
 #![crate_type = "dylib"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -27,10 +26,12 @@
 #![feature(custom_attribute)]
 #![feature(optin_builtin_traits)]
 #![allow(unused_attributes)]
-#![feature(rustc_private)]
-#![feature(staged_api)]
 #![feature(specialization)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(rustc_private))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 use std::cell::{Cell, RefCell};
 use std::ops::{Add, Sub};
 use std::rc::Rc;

src/libterm/lib.rs

@@ -41,9 +41,6 @@
 //! [ti]: https://en.wikipedia.org/wiki/Terminfo
 
 #![crate_name = "term"]
-#![unstable(feature = "rustc_private",
-            reason = "use the crates.io `term` library instead",
-            issue = "27812")]
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
@@ -54,13 +51,15 @@
 #![deny(missing_docs)]
 #![deny(warnings)]
 
-#![feature(box_syntax)]
 #![feature(staged_api)]
 #![cfg_attr(windows, feature(libc))]
 // Handle rustfmt skips
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
 
+#![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
+#![cfg_attr(stage0, feature(staged_api))]
+
 use std::io::prelude::*;
 
 pub use terminfo::TerminfoTerminal;