4 files changed, 24 insertions, 9 deletions
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index 67430e5bbda..513e22a788c 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -705,7 +705,8 @@ extern "rust-intrinsic" {
                          they should be used through stabilized interfaces \
                          in the rest of the standard library",
                issue = "0")]
-    #[rustc_deprecated(reason = "no longer used by rustc, will be removed - use MaybeUnint instead",
+    #[rustc_deprecated(reason = "no longer used by rustc, will be removed - use MaybeUninit \
+                                 instead",
                        since = "1.38.0")]
     pub fn init<T>() -> T;
 
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index 2e999a0682b..293a2dd9492 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -1244,12 +1244,14 @@ mod builtin {
 
     /// Attribute macro applied to a function to turn it into a unit test.
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]
     pub macro test($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a function to turn it into a benchmark test.
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]
     pub macro bench($item:item) { /* compiler built-in */ }
@@ -1257,6 +1259,7 @@ mod builtin {
     /// An implementation detail of the `#[test]` and `#[bench]` macros.
     #[unstable(feature = "custom_test_frameworks", issue = "50297",
                reason = "custom test frameworks are an unstable feature")]
+    #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]
     pub macro test_case($item:item) { /* compiler built-in */ }
diff --git a/src/libcore/ops/try.rs b/src/libcore/ops/try.rs
index 9fa2c81954e..76fec1020f1 100644
--- a/src/libcore/ops/try.rs
+++ b/src/libcore/ops/try.rs
@@ -8,12 +8,12 @@
 #[rustc_on_unimplemented(
    on(all(
        any(from_method="from_error", from_method="from_ok"),
-       from_desugaring="?"),
+       from_desugaring="QuestionMark"),
       message="the `?` operator can only be used in a \
                function that returns `Result` or `Option` \
                (or another type that implements `{Try}`)",
       label="cannot use the `?` operator in a function that returns `{Self}`"),
-   on(all(from_method="into_result", from_desugaring="?"),
+   on(all(from_method="into_result", from_desugaring="QuestionMark"),
       message="the `?` operator can only be applied to values \
                that implement `{Try}`",
       label="the `?` operator cannot be applied to type `{Self}`")
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index fdf3cc8e006..363ae088275 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -5342,13 +5342,24 @@ impl<A, B> SlicePartialEq<B> for [A]
             return false;
         }
 
-        for i in 0..self.len() {
-            if !self[i].eq(&other[i]) {
-                return false;
-            }
+        self.iter().zip(other.iter()).all(|(x, y)| x == y)
+    }
+}
+
+// Use an equal-pointer optimization when types are `Eq`
+impl<A> SlicePartialEq<A> for [A]
+    where A: PartialEq<A> + Eq
+{
+    default fn equal(&self, other: &[A]) -> bool {
+        if self.len() != other.len() {
+            return false;
+        }
+
+        if self.as_ptr() == other.as_ptr() {
+            return true;
         }
 
-        true
+        self.iter().zip(other.iter()).all(|(x, y)| x == y)
     }
 }
 
@@ -5457,7 +5468,7 @@ impl SliceOrd<u8> for [u8] {
 #[doc(hidden)]
 /// Trait implemented for types that can be compared for equality using
 /// their bytewise representation
-trait BytewiseEquality { }
+trait BytewiseEquality: Eq + Copy { }
 
 macro_rules! impl_marker_for {
     ($traitname:ident, $($ty:ty)*) => {