change #![feature(const_fn)] to specific gates

49 files changed, 127 insertions, 75 deletions

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index e0a3b8d52f4..b9c5ff10f87 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -329,6 +329,7 @@ impl<T> Cell<T> {
     /// let c = Cell::new(5);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_cell_new"))]
     #[inline]
     pub const fn new(value: T) -> Cell<T> {
         Cell {
@@ -543,6 +544,7 @@ impl<T> RefCell<T> {
     /// let c = RefCell::new(5);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_refcell_new"))]
     #[inline]
     pub const fn new(value: T) -> RefCell<T> {
         RefCell {
@@ -1188,6 +1190,7 @@ impl<T> UnsafeCell<T> {
     /// let uc = UnsafeCell::new(5);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_unsafe_cell_new"))]
     #[inline]
     pub const fn new(value: T) -> UnsafeCell<T> {
         UnsafeCell { value: value }
diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index c270c6ae0db..69612bd2a32 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -85,12 +85,30 @@
 #![feature(prelude_import)]
 #![feature(repr_simd, platform_intrinsics)]
 #![feature(rustc_attrs)]
+#![cfg_attr(not(stage0), feature(rustc_const_unstable))]
 #![feature(specialization)]
 #![feature(staged_api)]
 #![feature(unboxed_closures)]
 #![feature(untagged_unions)]
 #![feature(unwind_attributes)]
 
+#![cfg_attr(not(stage0), feature(const_min_value))]
+#![cfg_attr(not(stage0), feature(const_max_value))]
+#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_isize_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_usize_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_i8_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_u8_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_i16_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_u16_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_i32_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_u32_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_i64_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_u64_new))]
+#![cfg_attr(not(stage0), feature(const_unsafe_cell_new))]
+#![cfg_attr(not(stage0), feature(const_cell_new))]
+#![cfg_attr(not(stage0), feature(const_nonzero_new))]
+
 #[prelude_import]
 #[allow(unused)]
 use prelude::v1::*;
diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index af2f876a2f3..7c82b00f2cf 100644
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -189,6 +189,7 @@ pub fn forget<T>(t: T) {
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_size_of"))]
 pub const fn size_of<T>() -> usize {
     unsafe { intrinsics::size_of::<T>() }
 }
@@ -280,6 +281,7 @@ pub fn min_align_of_val<T: ?Sized>(val: &T) -> usize {
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_align_of"))]
 pub const fn align_of<T>() -> usize {
     unsafe { intrinsics::min_align_of::<T>() }
 }
diff --git a/src/libcore/nonzero.rs b/src/libcore/nonzero.rs
index 3ff1068b937..f075d825f5d 100644
--- a/src/libcore/nonzero.rs
+++ b/src/libcore/nonzero.rs
@@ -68,6 +68,10 @@ pub struct NonZero<T: Zeroable>(T);
 impl<T: Zeroable> NonZero<T> {
     /// Creates an instance of NonZero with the provided value.
     /// You must indeed ensure that the value is actually "non-zero".
+    #[unstable(feature = "nonzero",
+               reason = "needs an RFC to flesh out the design",
+               issue = "27730")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_nonzero_new"))]
     #[inline]
     pub const unsafe fn new_unchecked(inner: T) -> Self {
         NonZero(inner)
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index c5175287ccf..bf31deae7a6 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -109,6 +109,7 @@ macro_rules! int_impl {
         /// assert_eq!(i8::min_value(), -128);
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_min_value"))]
         #[inline]
         pub const fn min_value() -> Self {
             !0 ^ ((!0 as $UnsignedT) >> 1) as Self
@@ -122,6 +123,7 @@ macro_rules! int_impl {
         /// assert_eq!(i8::max_value(), 127);
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_max_value"))]
         #[inline]
         pub const fn max_value() -> Self {
             !Self::min_value()
@@ -1280,6 +1282,7 @@ macro_rules! uint_impl {
         /// assert_eq!(u8::min_value(), 0);
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_min_value"))]
         #[inline]
         pub const fn min_value() -> Self { 0 }
 
@@ -1291,6 +1294,7 @@ macro_rules! uint_impl {
         /// assert_eq!(u8::max_value(), 255);
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
+        #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_max_value"))]
         #[inline]
         pub const fn max_value() -> Self { !0 }
 
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index 2e42e0dfd55..20aa881f4bc 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -76,6 +76,7 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_null"))]
 pub const fn null<T>() -> *const T { 0 as *const T }
 
 /// Creates a null mutable raw pointer.
@@ -90,6 +91,7 @@ pub const fn null<T>() -> *const T { 0 as *const T }
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_null_mut"))]
 pub const fn null_mut<T>() -> *mut T { 0 as *mut T }
 
 /// Swaps the values at two mutable locations of the same type, without
@@ -1097,6 +1099,8 @@ impl<T: ?Sized> Unique<T> {
     /// # Safety
     ///
     /// `ptr` must be non-null.
+    #[unstable(feature = "unique", issue = "27730")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_unique_new"))]
     pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
         Unique { pointer: NonZero::new_unchecked(ptr), _marker: PhantomData }
     }
@@ -1230,6 +1234,8 @@ impl<T: ?Sized> Shared<T> {
     /// # Safety
     ///
     /// `ptr` must be non-null.
+    #[unstable(feature = "shared", issue = "27730")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_shared_new"))]
     pub const unsafe fn new_unchecked(ptr: *mut T) -> Self {
         Shared { pointer: NonZero::new_unchecked(ptr), _marker: PhantomData }
     }
diff --git a/src/libcore/sync/atomic.rs b/src/libcore/sync/atomic.rs
index 510e01db0e9..09f3586a8c9 100644
--- a/src/libcore/sync/atomic.rs
+++ b/src/libcore/sync/atomic.rs
@@ -241,6 +241,7 @@ impl AtomicBool {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_atomic_bool_new"))]
     pub const fn new(v: bool) -> AtomicBool {
         AtomicBool { v: UnsafeCell::new(v as u8) }
     }
@@ -649,6 +650,7 @@ impl<T> AtomicPtr<T> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_atomic_ptr_new"))]
     pub const fn new(p: *mut T) -> AtomicPtr<T> {
         AtomicPtr { p: UnsafeCell::new(p) }
     }
@@ -920,7 +922,7 @@ impl<T> AtomicPtr<T> {
 
 #[cfg(target_has_atomic = "ptr")]
 macro_rules! atomic_int {
-    ($stable:meta,
+    ($stable:meta, $const_unstable:meta,
      $stable_cxchg:meta,
      $stable_debug:meta,
      $stable_access:meta,
@@ -969,6 +971,7 @@ macro_rules! atomic_int {
             /// ```
             #[inline]
             #[$stable]
+            #[cfg_attr(not(stage0), $const_unstable)]
             pub const fn new(v: $int_type) -> Self {
                 $atomic_type {v: UnsafeCell::new(v)}
             }
@@ -1332,6 +1335,7 @@ macro_rules! atomic_int {
 #[cfg(target_has_atomic = "8")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_i8_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1340,6 +1344,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "8")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_u8_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1348,6 +1353,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "16")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_i16_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1356,6 +1362,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "16")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_u16_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1364,6 +1371,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "32")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_i32_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1372,6 +1380,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "32")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_u32_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1380,6 +1389,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "64")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_i64_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1388,6 +1398,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "64")]
 atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
+    rustc_const_unstable(feature = "const_atomic_u64_new"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
@@ -1396,6 +1407,7 @@ atomic_int! {
 #[cfg(target_has_atomic = "ptr")]
 atomic_int!{
     stable(feature = "rust1", since = "1.0.0"),
+    rustc_const_unstable(feature = "const_atomic_isize_new"),
     stable(feature = "extended_compare_and_swap", since = "1.10.0"),
     stable(feature = "atomic_debug", since = "1.3.0"),
     stable(feature = "atomic_access", since = "1.15.0"),
@@ -1404,6 +1416,7 @@ atomic_int!{
 #[cfg(target_has_atomic = "ptr")]
 atomic_int!{
     stable(feature = "rust1", since = "1.0.0"),
+    rustc_const_unstable(feature = "const_atomic_usize_new"),
     stable(feature = "extended_compare_and_swap", since = "1.10.0"),
     stable(feature = "atomic_debug", since = "1.3.0"),
     stable(feature = "atomic_access", since = "1.15.0"),
diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs
index ab2022b1824..ce4d14b222c 100644
--- a/src/libcore/tests/lib.rs
+++ b/src/libcore/tests/lib.rs
@@ -11,7 +11,6 @@
 #![deny(warnings)]
 
 #![feature(box_syntax)]
-#![feature(const_fn)]
 #![feature(core_float)]
 #![feature(core_private_bignum)]
 #![feature(core_private_diy_float)]
@@ -42,6 +41,10 @@
 #![feature(try_from)]
 #![feature(unique)]
 
+#![feature(const_atomic_bool_new)]
+#![feature(const_atomic_usize_new)]
+#![feature(const_atomic_isize_new)]
+
 extern crate core;
 extern crate test;
 extern crate rand;
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index 82f01c36fee..df97f2fb8bc 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -22,7 +22,6 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(conservative_impl_trait)]
-#![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(i128_type)]
 #![cfg_attr(windows, feature(libc))]
@@ -36,6 +35,9 @@
 #![feature(trace_macros)]
 #![feature(test)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
+
 #![recursion_limit="256"]
 
 extern crate arena;
diff --git a/src/librustc_apfloat/lib.rs b/src/librustc_apfloat/lib.rs
index d4a02065761..c13141008a4 100644
--- a/src/librustc_apfloat/lib.rs
+++ b/src/librustc_apfloat/lib.rs
@@ -45,11 +45,14 @@
 #![deny(warnings)]
 #![forbid(unsafe_code)]
 
-#![feature(const_fn)]
 #![feature(i128_type)]
 #![feature(slice_patterns)]
 #![feature(try_from)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_min_value))]
+#![cfg_attr(not(stage0), feature(const_max_value))]
+
 #[macro_use]
 extern crate rustc_bitflags;
 
diff --git a/src/librustc_const_eval/lib.rs b/src/librustc_const_eval/lib.rs
index 9fedee80d46..0c3606cab10 100644
--- a/src/librustc_const_eval/lib.rs
+++ b/src/librustc_const_eval/lib.rs
@@ -23,9 +23,11 @@
 #![feature(slice_patterns)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(const_fn)]
 #![feature(i128_type)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_min_value))]
+
 extern crate arena;
 #[macro_use] extern crate syntax;
 #[macro_use] extern crate log;
diff --git a/src/librustc_const_math/lib.rs b/src/librustc_const_math/lib.rs
index 93b70ef8e4a..0533f10104a 100644
--- a/src/librustc_const_math/lib.rs
+++ b/src/librustc_const_math/lib.rs
@@ -19,10 +19,13 @@
       html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
-#![feature(const_fn)]
 #![feature(i128)]
 #![feature(i128_type)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_min_value))]
+#![cfg_attr(not(stage0), feature(const_max_value))]
+
 extern crate rustc_apfloat;
 
 extern crate syntax;
diff --git a/src/librustc_mir/diagnostics.rs b/src/librustc_mir/diagnostics.rs
index 4b71a429f84..26436d54ac8 100644
--- a/src/librustc_mir/diagnostics.rs
+++ b/src/librustc_mir/diagnostics.rs
@@ -384,7 +384,7 @@ static B: &'static AtomicUsize = &A; // ok!
 You can also have this error while using a cell type:
 
 ```compile_fail,E0492
-#![feature(const_fn)]
+#![feature(const_cell_new)]
 
 use std::cell::Cell;
 
@@ -412,7 +412,7 @@ However, if you still wish to use these types, you can achieve this by an unsafe
 wrapper:
 
 ```
-#![feature(const_fn)]
+#![feature(const_cell_new)]
 
 use std::cell::Cell;
 use std::marker::Sync;
diff --git a/src/librustc_trans/lib.rs b/src/librustc_trans/lib.rs
index 63fd37c2b98..256200a6e95 100644
--- a/src/librustc_trans/lib.rs
+++ b/src/librustc_trans/lib.rs
@@ -21,7 +21,6 @@
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(const_fn)]
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
 #![feature(i128_type)]
@@ -31,6 +30,10 @@
 #![feature(slice_patterns)]
 #![feature(conservative_impl_trait)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
+#![cfg_attr(not(stage0), feature(const_once_new))]
+
 use rustc::dep_graph::WorkProduct;
 use syntax_pos::symbol::Symbol;
 
diff --git a/src/librustc_trans_utils/lib.rs b/src/librustc_trans_utils/lib.rs
index 90e17906328..5e8abe59ad9 100644
--- a/src/librustc_trans_utils/lib.rs
+++ b/src/librustc_trans_utils/lib.rs
@@ -19,7 +19,6 @@
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(const_fn)]
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
 #![feature(i128_type)]
@@ -28,6 +27,8 @@
 #![feature(slice_patterns)]
 #![feature(conservative_impl_trait)]
 
+#![cfg_attr(stage0, feature(const_fn))]
+
 extern crate rustc;
 extern crate syntax;
 extern crate syntax_pos;
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 33bf0d68126..aa1337a9da0 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -292,6 +292,7 @@
 #![feature(raw)]
 #![feature(repr_simd)]
 #![feature(rustc_attrs)]
+#![cfg_attr(not(stage0), feature(rustc_const_unstable))]
 #![feature(shared)]
 #![feature(sip_hash_13)]
 #![feature(slice_bytes)]
@@ -315,6 +316,17 @@
 #![feature(doc_cfg)]
 #![cfg_attr(test, feature(update_panic_count))]
 
+#![cfg_attr(not(stage0), feature(const_max_value))]
+#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_isize_new))]
+#![cfg_attr(not(stage0), feature(const_atomic_usize_new))]
+#![cfg_attr(all(not(stage0), windows), feature(const_atomic_ptr_new))]
+#![cfg_attr(not(stage0), feature(const_unsafe_cell_new))]
+#![cfg_attr(not(stage0), feature(const_cell_new))]
+#![cfg_attr(not(stage0), feature(const_once_new))]
+#![cfg_attr(not(stage0), feature(const_ptr_null))]
+#![cfg_attr(not(stage0), feature(const_ptr_null_mut))]
+
 #![default_lib_allocator]
 
 // Always use alloc_system during stage0 since we don't know if the alloc_*
diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index 403685a4b8e..015106fc2e5 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -156,6 +156,7 @@ struct Finish {
 impl Once {
     /// Creates a new `Once` value.
     #[stable(feature = "once_new", since = "1.2.0")]
+    #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_once_new"))]
     pub const fn new() -> Once {
         Once {
             state: AtomicUsize::new(INCOMPLETE),
diff --git a/src/test/compile-fail-fulldeps/dropck_tarena_cycle_checked.rs b/src/test/compile-fail-fulldeps/dropck_tarena_cycle_checked.rs
index 7de6e58c784..fa85432fb8e 100644
--- a/src/test/compile-fail-fulldeps/dropck_tarena_cycle_checked.rs
+++ b/src/test/compile-fail-fulldeps/dropck_tarena_cycle_checked.rs
@@ -16,7 +16,8 @@
 //  which is a reduction of this code to more directly show the reason
 //  for the error message we see here.)
 
-#![feature(const_fn, rustc_private)]
+#![feature(rustc_private)]
+#![feature(const_atomic_usize_new)]
 
 extern crate arena;
 
diff --git a/src/test/compile-fail/const-call.rs b/src/test/compile-fail/const-call.rs
index 0745ac02d07..18476494300 100644
--- a/src/test/compile-fail/const-call.rs
+++ b/src/test/compile-fail/const-call.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
-
 fn f(x: usize) -> usize {
     x
 }
diff --git a/src/test/compile-fail/dropck_trait_cycle_checked.rs b/src/test/compile-fail/dropck_trait_cycle_checked.rs
index e701718028a..c0f0e3650d9 100644
--- a/src/test/compile-fail/dropck_trait_cycle_checked.rs
+++ b/src/test/compile-fail/dropck_trait_cycle_checked.rs
@@ -13,7 +13,7 @@
 //
 // (Compare against compile-fail/dropck_vec_cycle_checked.rs)
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::cell::Cell;
 use id::Id;
diff --git a/src/test/compile-fail/functional-struct-update-respects-privacy.rs b/src/test/compile-fail/functional-struct-update-respects-privacy.rs
index d2df0d9ef27..3f41401eb69 100644
--- a/src/test/compile-fail/functional-struct-update-respects-privacy.rs
+++ b/src/test/compile-fail/functional-struct-update-respects-privacy.rs
@@ -10,8 +10,6 @@
 
 // RFC 736 (and Issue 21407): functional struct update should respect privacy.
 
-#![feature(const_fn)]
-
 // The `foo` module attempts to maintains an invariant that each `S`
 // has a unique `u64` id.
 use self::foo::S;
diff --git a/src/test/compile-fail/issue-17718-const-borrow.rs b/src/test/compile-fail/issue-17718-const-borrow.rs
index 327b6946822..1464fcd9a1c 100644
--- a/src/test/compile-fail/issue-17718-const-borrow.rs
+++ b/src/test/compile-fail/issue-17718-const-borrow.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
+#![feature(const_unsafe_cell_new)]
 
 use std::cell::UnsafeCell;
 
diff --git a/src/test/compile-fail/issue-43733-2.rs b/src/test/compile-fail/issue-43733-2.rs
index 0fd31454596..1bf165c89d3 100644
--- a/src/test/compile-fail/issue-43733-2.rs
+++ b/src/test/compile-fail/issue-43733-2.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
+#![feature(const_fn, const_cell_new, const_unsafe_cell_new)]
 #![feature(cfg_target_thread_local, thread_local_internals)]
 
 // On platforms *without* `#[thread_local]`, use
diff --git a/src/test/compile-fail/issue-7364.rs b/src/test/compile-fail/issue-7364.rs
index bd32317ae78..ef53be75780 100644
--- a/src/test/compile-fail/issue-7364.rs
+++ b/src/test/compile-fail/issue-7364.rs
@@ -8,9 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(box_syntax)]
-#![feature(const_fn)]
-#![allow(warnings)]
+#![feature(box_syntax, const_refcell_new)]
 
 use std::cell::RefCell;
 
@@ -18,5 +16,6 @@ use std::cell::RefCell;
 static boxed: Box<RefCell<isize>> = box RefCell::new(0);
 //~^ ERROR allocations are not allowed in statics
 //~| ERROR `std::cell::RefCell<isize>: std::marker::Sync` is not satisfied
+//~| WARN unsupported constant expr
 
 fn main() { }
diff --git a/src/test/debuginfo/constant-debug-locs.rs b/src/test/debuginfo/constant-debug-locs.rs
index 7b7bda30225..7a24510b7d4 100644
--- a/src/test/debuginfo/constant-debug-locs.rs
+++ b/src/test/debuginfo/constant-debug-locs.rs
@@ -15,7 +15,7 @@
 #![allow(dead_code, unused_variables)]
 #![feature(omit_gdb_pretty_printer_section)]
 #![omit_gdb_pretty_printer_section]
-#![feature(const_fn)]
+#![feature(const_unsafe_cell_new)]
 #![feature(static_mutex)]
 
 // This test makes sure that the compiler doesn't crash when trying to assign
diff --git a/src/test/run-pass-valgrind/cast-enum-with-dtor.rs b/src/test/run-pass-valgrind/cast-enum-with-dtor.rs
index 2815863fe99..439c1080f47 100644
--- a/src/test/run-pass-valgrind/cast-enum-with-dtor.rs
+++ b/src/test/run-pass-valgrind/cast-enum-with-dtor.rs
@@ -11,7 +11,7 @@
 // no-prefer-dynamic
 
 #![allow(dead_code)]
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 // check dtor calling order when casting enums.
 
diff --git a/src/test/run-pass/associated-types-project-from-type-param-via-bound-in-where-clause.rs b/src/test/run-pass/associated-types-project-from-type-param-via-bound-in-where-clause.rs
index 8dc7d79ec2a..7cde780cc54 100644
--- a/src/test/run-pass/associated-types-project-from-type-param-via-bound-in-where-clause.rs
+++ b/src/test/run-pass/associated-types-project-from-type-param-via-bound-in-where-clause.rs
@@ -12,7 +12,7 @@
 // `Item` originates in a where-clause, not the declaration of
 // `T`. Issue #20300.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::marker::{PhantomData};
 use std::sync::atomic::{AtomicUsize};
diff --git a/src/test/run-pass/auxiliary/const_fn_lib.rs b/src/test/run-pass/auxiliary/const_fn_lib.rs
index b0d5a6b1272..be06e8dd570 100644
--- a/src/test/run-pass/auxiliary/const_fn_lib.rs
+++ b/src/test/run-pass/auxiliary/const_fn_lib.rs
@@ -13,4 +13,4 @@
 #![crate_type="rlib"]
 #![feature(const_fn)]
 
-pub const fn foo() -> usize { 22 } //~ ERROR const fn is unstable
+pub const fn foo() -> usize { 22 }
diff --git a/src/test/run-pass/auxiliary/issue-17718-aux.rs b/src/test/run-pass/auxiliary/issue-17718-aux.rs
index cf7fdd7f983..36891a1ecad 100644
--- a/src/test/run-pass/auxiliary/issue-17718-aux.rs
+++ b/src/test/run-pass/auxiliary/issue-17718-aux.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic;
 
diff --git a/src/test/run-pass/auxiliary/thread-local-extern-static.rs b/src/test/run-pass/auxiliary/thread-local-extern-static.rs
index e9457886be8..bce87ef5a26 100644
--- a/src/test/run-pass/auxiliary/thread-local-extern-static.rs
+++ b/src/test/run-pass/auxiliary/thread-local-extern-static.rs
@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![feature(cfg_target_thread_local, const_fn, thread_local)]
+#![feature(const_cell_new)]
 #![crate_type = "lib"]
 
 #[cfg(target_thread_local)]
diff --git a/src/test/run-pass/box-of-array-of-drop-1.rs b/src/test/run-pass/box-of-array-of-drop-1.rs
index a63a232e1b5..47b44863a74 100644
--- a/src/test/run-pass/box-of-array-of-drop-1.rs
+++ b/src/test/run-pass/box-of-array-of-drop-1.rs
@@ -13,7 +13,7 @@
 
 // ignore-emscripten no threads support
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
diff --git a/src/test/run-pass/box-of-array-of-drop-2.rs b/src/test/run-pass/box-of-array-of-drop-2.rs
index ca179429172..54be4955baf 100644
--- a/src/test/run-pass/box-of-array-of-drop-2.rs
+++ b/src/test/run-pass/box-of-array-of-drop-2.rs
@@ -13,7 +13,7 @@
 
 // ignore-emscripten no threads support
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
diff --git a/src/test/run-pass/const-fn-cross-crate.rs b/src/test/run-pass/const-fn-cross-crate.rs
deleted file mode 100644
index 7b4b751fd7f..00000000000
--- a/src/test/run-pass/const-fn-cross-crate.rs
+++ /dev/null
@@ -1,26 +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.
-
-// aux-build:const_fn_lib.rs
-
-// A very basic test of const fn functionality.
-
-#![feature(const_fn)]
-
-extern crate const_fn_lib;
-
-use const_fn_lib::foo;
-
-const FOO: usize = foo();
-
-fn main() {
-    assert_eq!(FOO, 22);
-    let _: [i32; foo()] = [42; 22];
-}
diff --git a/src/test/compile-fail/const-fn-stability-calls.rs b/src/test/run-pass/const-fn-stability-calls.rs
index 609077663ef..c5f97d55c06 100644
--- a/src/test/compile-fail/const-fn-stability-calls.rs
+++ b/src/test/run-pass/const-fn-stability-calls.rs
@@ -16,8 +16,8 @@ extern crate const_fn_lib;
 
 use const_fn_lib::foo;
 
-static FOO: usize = foo(); //~ ERROR const fns are an unstable feature
-const BAR: usize = foo(); //~ ERROR const fns are an unstable feature
+static FOO: usize = foo();
+const BAR: usize = foo();
 
 macro_rules! constant {
     ($n:ident: $t:ty = $v:expr) => {
@@ -26,9 +26,9 @@ macro_rules! constant {
 }
 
 constant! {
-    BAZ: usize = foo() //~ ERROR const fns are an unstable feature
+    BAZ: usize = foo()
 }
 
 fn main() {
-//    let x: [usize; foo()] = [];
+    let x: [usize; foo()] = [42; foo()];
 }
diff --git a/src/test/run-pass/const-size_of-align_of.rs b/src/test/run-pass/const-size_of-align_of.rs
index 06fbe9bf4f6..d5547ea5add 100644
--- a/src/test/run-pass/const-size_of-align_of.rs
+++ b/src/test/run-pass/const-size_of-align_of.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
+#![feature(const_fn, const_size_of, const_align_of)]
 
 use std::mem;
 
diff --git a/src/test/run-pass/issue-17718-static-unsafe-interior.rs b/src/test/run-pass/issue-17718-static-unsafe-interior.rs
index 993e5e1c1e6..66f70cdaeb0 100644
--- a/src/test/run-pass/issue-17718-static-unsafe-interior.rs
+++ b/src/test/run-pass/issue-17718-static-unsafe-interior.rs
@@ -11,8 +11,7 @@
 // pretty-expanded FIXME #23616
 
 #![feature(core)]
-#![feature(const_fn)]
-
+#![feature(const_unsafe_cell_new)]
 
 use std::marker;
 use std::cell::UnsafeCell;
diff --git a/src/test/run-pass/issue-17718.rs b/src/test/run-pass/issue-17718.rs
index 744e63f159b..1b8fbc1ad2f 100644
--- a/src/test/run-pass/issue-17718.rs
+++ b/src/test/run-pass/issue-17718.rs
@@ -12,7 +12,7 @@
 
 
 #![feature(core)]
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 extern crate issue_17718_aux as other;
 
diff --git a/src/test/run-pass/issue-21486.rs b/src/test/run-pass/issue-21486.rs
index 699189a4e6a..23d06c4324d 100644
--- a/src/test/run-pass/issue-21486.rs
+++ b/src/test/run-pass/issue-21486.rs
@@ -12,7 +12,7 @@
 // created via FRU and control-flow breaks in the middle of
 // construction.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic::{Ordering, AtomicUsize};
 
diff --git a/src/test/run-pass/issue-26655.rs b/src/test/run-pass/issue-26655.rs
index 402460e7253..3e252b8629e 100644
--- a/src/test/run-pass/issue-26655.rs
+++ b/src/test/run-pass/issue-26655.rs
@@ -10,10 +10,10 @@
 
 // ignore-emscripten no threads support
 
-#![feature(const_fn)]
-
 // Check that the destructors of simple enums are run on unwinding
 
+#![feature(const_atomic_usize_new)]
+
 use std::sync::atomic::{Ordering, AtomicUsize};
 use std::thread;
 
diff --git a/src/test/run-pass/issue-27997.rs b/src/test/run-pass/issue-27997.rs
index cd81f689693..dab42e48e16 100644
--- a/src/test/run-pass/issue-27997.rs
+++ b/src/test/run-pass/issue-27997.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic::{Ordering, AtomicUsize};
 
diff --git a/src/test/run-pass/nested-vec-3.rs b/src/test/run-pass/nested-vec-3.rs
index 458b6c16e62..9141b5f29ce 100644
--- a/src/test/run-pass/nested-vec-3.rs
+++ b/src/test/run-pass/nested-vec-3.rs
@@ -14,7 +14,7 @@
 // the contents implement Drop and we hit a panic in the middle of
 // construction.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
diff --git a/src/test/run-pass/panic-handler-chain.rs b/src/test/run-pass/panic-handler-chain.rs
index 1ad43f5f17f..c5dc8ccd2ee 100644
--- a/src/test/run-pass/panic-handler-chain.rs
+++ b/src/test/run-pass/panic-handler-chain.rs
@@ -10,7 +10,8 @@
 
 // ignore-emscripten no threads support
 
-#![feature(panic_handler, const_fn, std_panic)]
+#![feature(panic_handler, std_panic)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::panic;
diff --git a/src/test/run-pass/panic-handler-set-twice.rs b/src/test/run-pass/panic-handler-set-twice.rs
index 196e08a63a7..8bf2683cd9f 100644
--- a/src/test/run-pass/panic-handler-set-twice.rs
+++ b/src/test/run-pass/panic-handler-set-twice.rs
@@ -7,7 +7,8 @@
 // <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.
-#![feature(panic_handler, const_fn, std_panic)]
+#![feature(panic_handler, std_panic)]
+#![feature(const_atomic_usize_new)]
 
 // ignore-emscripten no threads support
 
diff --git a/src/test/run-pass/struct-order-of-eval-3.rs b/src/test/run-pass/struct-order-of-eval-3.rs
index b67eb205396..cf93133d205 100644
--- a/src/test/run-pass/struct-order-of-eval-3.rs
+++ b/src/test/run-pass/struct-order-of-eval-3.rs
@@ -11,7 +11,7 @@
 // Checks that functional-record-update order-of-eval is as expected
 // even when no Drop-implementations are involved.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic::{Ordering, AtomicUsize};
 
diff --git a/src/test/run-pass/struct-order-of-eval-4.rs b/src/test/run-pass/struct-order-of-eval-4.rs
index 20d27d8b309..d442923478f 100644
--- a/src/test/run-pass/struct-order-of-eval-4.rs
+++ b/src/test/run-pass/struct-order-of-eval-4.rs
@@ -11,7 +11,7 @@
 // Checks that struct-literal expression order-of-eval is as expected
 // even when no Drop-implementations are involved.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::sync::atomic::{Ordering, AtomicUsize};
 
diff --git a/src/test/run-pass/vector-sort-panic-safe.rs b/src/test/run-pass/vector-sort-panic-safe.rs
index 4387a43f03b..c6a1859de30 100644
--- a/src/test/run-pass/vector-sort-panic-safe.rs
+++ b/src/test/run-pass/vector-sort-panic-safe.rs
@@ -10,9 +10,9 @@
 
 // ignore-emscripten no threads support
 
-#![feature(const_fn)]
 #![feature(rand)]
 #![feature(sort_unstable)]
+#![feature(const_atomic_usize_new)]
 
 use std::__rand::{thread_rng, Rng};
 use std::cell::Cell;
diff --git a/src/test/ui/span/dropck_arr_cycle_checked.rs b/src/test/ui/span/dropck_arr_cycle_checked.rs
index 8e8b3c24c76..995a198271c 100644
--- a/src/test/ui/span/dropck_arr_cycle_checked.rs
+++ b/src/test/ui/span/dropck_arr_cycle_checked.rs
@@ -13,7 +13,7 @@
 //
 // (Compare against compile-fail/dropck_vec_cycle_checked.rs)
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::cell::Cell;
 use id::Id;
diff --git a/src/test/ui/span/dropck_vec_cycle_checked.rs b/src/test/ui/span/dropck_vec_cycle_checked.rs
index 65db2a56b7d..5bcaa71f73c 100644
--- a/src/test/ui/span/dropck_vec_cycle_checked.rs
+++ b/src/test/ui/span/dropck_vec_cycle_checked.rs
@@ -12,7 +12,7 @@
 //
 // (Compare against compile-fail/dropck_arr_cycle_checked.rs)
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::cell::Cell;
 use id::Id;
diff --git a/src/test/ui/span/vec-must-not-hide-type-from-dropck.rs b/src/test/ui/span/vec-must-not-hide-type-from-dropck.rs
index 310ab20489a..d99f3bb19db 100644
--- a/src/test/ui/span/vec-must-not-hide-type-from-dropck.rs
+++ b/src/test/ui/span/vec-must-not-hide-type-from-dropck.rs
@@ -23,7 +23,7 @@
 // conditions above to be satisfied, meaning that if the dropck is
 // sound, it should reject this code.
 
-#![feature(const_fn)]
+#![feature(const_atomic_usize_new)]
 
 use std::cell::Cell;
 use id::Id;