Reuse the staged_api feature for rustc_const_unstable

src/liballoc/lib.rs

@@ -117,7 +117,7 @@
 #![feature(unsized_locals)]
 #![feature(allocator_internals)]
 #![cfg_attr(bootstrap, feature(on_unimplemented))]
-#![feature(rustc_const_unstable)]
+#![cfg_attr(bootstrap, feature(rustc_const_unstable))]
 #![feature(slice_partition_dedup)]
 #![feature(maybe_uninit_extra, maybe_uninit_slice)]
 #![feature(alloc_layout_extra)]

src/libcore/lib.rs

@@ -96,7 +96,7 @@
 #![feature(prelude_import)]
 #![feature(repr_simd, platform_intrinsics)]
 #![feature(rustc_attrs)]
-#![feature(rustc_const_unstable)]
+#![cfg_attr(bootstrap, feature(rustc_const_unstable))]
 #![feature(simd_ffi)]
 #![feature(specialization)]
 #![feature(staged_api)]

src/librustc/middle/stability.rs

@@ -189,9 +189,14 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             }
         } else {
             // Emit errors for non-staged-api crates.
+            let unstable_attrs = [
+                sym::unstable, sym::stable,
+                sym::rustc_deprecated,
+                sym::rustc_const_unstable,
+            ];
             for attr in attrs {
                 let name = attr.name_or_empty();
-                if [sym::unstable, sym::stable, sym::rustc_deprecated].contains(&name) {
+                if unstable_attrs.contains(&name) {
                     attr::mark_used(attr);
                     struct_span_err!(
                         self.tcx.sess,

src/librustc_feature/active.rs

@@ -111,10 +111,6 @@ declare_features! (
     /// macros disappear).
     (active, allow_internal_unsafe, "1.0.0", None, None),
 
-    /// Allows using `#[rustc_const_unstable(feature = "foo", ..)]` which
-    /// lets a function to be `const` when opted into with `#![feature(foo)]`.
-    (active, rustc_const_unstable, "1.0.0", None, None),
-
     /// no-tracking-issue-end
 
     /// Allows using `#[link_name="llvm.*"]`.

src/librustc_feature/builtin_attrs.rs

@@ -344,10 +344,8 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         unstable, Whitelisted,
         template!(List: r#"feature = "name", reason = "...", issue = "N""#),
     ),
-    gated!(
-        rustc_const_unstable, Normal, template!(List: r#"feature = "name""#),
-        "the `#[rustc_const_unstable]` attribute is an internal feature",
-    ),
+    // FIXME(#14407)
+    ungated!(rustc_const_unstable, Whitelisted, template!(List: r#"feature = "name""#)),
     gated!(
         allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."),
         "allow_internal_unstable side-steps feature gating and stability checks",

src/libstd/lib.rs

@@ -293,7 +293,7 @@
 #![feature(raw)]
 #![feature(renamed_spin_loop)]
 #![feature(rustc_attrs)]
-#![feature(rustc_const_unstable)]
+#![cfg_attr(bootstrap, feature(rustc_const_unstable))]
 #![feature(rustc_private)]
 #![feature(shrink_to)]
 #![feature(slice_concat_ext)]

src/test/rustdoc/const-display.rs

@@ -4,7 +4,7 @@
             reason = "who ever let humans program computers, we're apparently really bad at it",
             issue = "0")]
 
-#![feature(rustc_const_unstable, const_fn, foo, foo2)]
+#![feature(const_fn, foo, foo2)]
 #![feature(staged_api)]
 
 // @has 'foo/fn.foo.html' '//pre' 'pub unsafe fn foo() -> u32'

src/test/ui/consts/const-eval/auxiliary/stability.rs

@@ -3,7 +3,7 @@
 #![crate_type="rlib"]
 #![stable(feature = "rust1", since = "1.0.0")]
 
-#![feature(rustc_const_unstable, const_fn)]
+#![feature(const_fn)]
 #![feature(staged_api)]
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/test/ui/consts/const-eval/dont_promote_unstable_const_fn.rs

@@ -3,7 +3,7 @@
             we're apparently really bad at it",
             issue = "0")]
 
-#![feature(rustc_const_unstable, const_fn)]
+#![feature(const_fn)]
 #![feature(staged_api)]
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.rs

@@ -3,7 +3,7 @@
             we're apparently really bad at it",
             issue = "0")]
 
-#![feature(rustc_const_unstable, const_fn, foo, foo2)]
+#![feature(const_fn, foo, foo2)]
 #![feature(staged_api)]
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.rs

@@ -3,7 +3,7 @@
             we're apparently really bad at it",
             issue = "0")]
 
-#![feature(rustc_const_unstable, const_fn, foo, foo2)]
+#![feature(const_fn, foo, foo2)]
 #![feature(staged_api)]
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.rs

@@ -3,7 +3,7 @@
             we're apparently really bad at it",
             issue = "0")]
 
-#![feature(rustc_const_unstable, const_fn, foo, foo2)]
+#![feature(const_fn, foo, foo2)]
 #![feature(staged_api)]
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/test/ui/feature-gate/allow-features-empty.rs

@@ -1,8 +1,6 @@
 // compile-flags: -Z allow_features=
 // Note: This test uses rustc internal flags because they will never stabilize.
 
-#![feature(rustc_const_unstable)] //~ ERROR
-
 #![feature(lang_items)] //~ ERROR
 
 #![feature(unknown_stdlib_feature)] //~ ERROR

src/test/ui/feature-gate/allow-features.rs

@@ -1,8 +1,6 @@
 // compile-flags: -Z allow_features=lang_items
 // Note: This test uses rustc internal flags because they will never stabilize.
 
-#![feature(rustc_const_unstable)] //~ ERROR
-
 #![feature(lang_items)]
 
 #![feature(unknown_stdlib_feature)] //~ ERROR

src/test/ui/feature-gates/feature-gate-rustc_const_unstable.rs

@@ -1,11 +1,8 @@
 // Test internal const fn feature gate.
 
-#![feature(staged_api)]
 #![feature(const_fn)]
-//#![feature(rustc_const_unstable)]
 
-#[stable(feature="zing", since="1.0.0")]
-#[rustc_const_unstable(feature="fzzzzzt")] //~ERROR internal feature
+#[rustc_const_unstable(feature="fzzzzzt")] //~ stability attributes may not be used outside
 pub const fn bazinga() {}
 
 fn main() {

src/test/ui/stability-attribute/stability-attribute-sanity.rs

@@ -1,6 +1,6 @@
 // Various checks that stability attributes are used correctly, per RFC 507
 
-#![feature(const_fn, staged_api, rustc_const_unstable)]
+#![feature(const_fn, staged_api)]
 
 #![stable(feature = "rust1", since = "1.0.0")]