4 files changed, 17 insertions, 13 deletions
diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index 239ff017cc2..beafddc5a10 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -494,7 +494,6 @@ impl<T: ?Sized> Cell<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(as_cell)]
     /// use std::cell::Cell;
     ///
     /// let slice: &mut [i32] = &mut [1, 2, 3];
@@ -504,7 +503,7 @@ impl<T: ?Sized> Cell<T> {
     /// assert_eq!(slice_cell.len(), 3);
     /// ```
     #[inline]
-    #[unstable(feature = "as_cell", issue="43038")]
+    #[stable(feature = "as_cell", since = "1.37.0")]
     pub fn from_mut(t: &mut T) -> &Cell<T> {
         unsafe {
             &*(t as *mut T as *const Cell<T>)
@@ -541,7 +540,6 @@ impl<T> Cell<[T]> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(as_cell)]
     /// use std::cell::Cell;
     ///
     /// let slice: &mut [i32] = &mut [1, 2, 3];
@@ -550,7 +548,7 @@ impl<T> Cell<[T]> {
     ///
     /// assert_eq!(slice_cell.len(), 3);
     /// ```
-    #[unstable(feature = "as_cell", issue="43038")]
+    #[stable(feature = "as_cell", since = "1.37.0")]
     pub fn as_slice_of_cells(&self) -> &[Cell<T>] {
         unsafe {
             &*(self as *const Cell<[T]> as *const [Cell<T>])
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index dd7090623f5..304b2fc9ebb 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1993,13 +1993,10 @@ assert_eq!((-10", stringify!($SelfT), ").signum(), -1);",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_int_sign")]
             #[inline]
-            pub fn signum(self) -> Self {
-                match self {
-                    n if n > 0 =>  1,
-                    0          =>  0,
-                    _          => -1,
-                }
+            pub const fn signum(self) -> Self {
+                (self > 0) as Self - (self < 0) as Self
             }
         }
 
diff --git a/src/test/run-pass/const-int-sign.rs b/src/test/run-pass/const-int-sign.rs
index 9d656a02030..fcd3ef4ea02 100644
--- a/src/test/run-pass/const-int-sign.rs
+++ b/src/test/run-pass/const-int-sign.rs
@@ -1,11 +1,21 @@
+#![feature(const_int_sign)]
+
 const NEGATIVE_A: bool = (-10i32).is_negative();
 const NEGATIVE_B: bool = 10i32.is_negative();
-const POSITIVE_A: bool= (-10i32).is_positive();
-const POSITIVE_B: bool= 10i32.is_positive();
+const POSITIVE_A: bool = (-10i32).is_positive();
+const POSITIVE_B: bool = 10i32.is_positive();
+
+const SIGNUM_POS: i32 = 10i32.signum();
+const SIGNUM_NIL: i32 = 0i32.signum();
+const SIGNUM_NEG: i32 = (-42i32).signum();
 
 fn main() {
     assert!(NEGATIVE_A);
     assert!(!NEGATIVE_B);
     assert!(!POSITIVE_A);
     assert!(POSITIVE_B);
+
+    assert_eq!(SIGNUM_POS, 1);
+    assert_eq!(SIGNUM_NIL, 0);
+    assert_eq!(SIGNUM_NEG, -1);
 }
diff --git a/src/test/run-pass/rfcs/rfc-1789-as-cell/from-mut.rs b/src/test/run-pass/rfcs/rfc-1789-as-cell/from-mut.rs
index f275c67fdf0..ea3ad7aed49 100644
--- a/src/test/run-pass/rfcs/rfc-1789-as-cell/from-mut.rs
+++ b/src/test/run-pass/rfcs/rfc-1789-as-cell/from-mut.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(as_cell)]
 
 use std::cell::Cell;