Auto merge of #39563 - frewsxcv:rollup, r=frewsxcv

Rollup of 19 pull requests

- Successful merges: #38518, #38921, #38959, #38983, #39009, #39107, #39193, #39289, #39312, #39393, #39442, #39443, #39453, #39454, #39471, #39477, #39478, #39527, #39552
- Failed merges:

11 files changed, 169 insertions, 39 deletions

diff --git a/src/libcore/char.rs b/src/libcore/char.rs
index 367422f5536..78764091cf0 100644
--- a/src/libcore/char.rs
+++ b/src/libcore/char.rs
@@ -588,7 +588,7 @@ impl ExactSizeIterator for EscapeUnicode {
 #[unstable(feature = "fused", issue = "35602")]
 impl FusedIterator for EscapeUnicode {}
 
-#[stable(feature = "char_struct_display", since = "1.17.0")]
+#[stable(feature = "char_struct_display", since = "1.16.0")]
 impl fmt::Display for EscapeUnicode {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         for c in self.clone() {
@@ -701,7 +701,7 @@ impl ExactSizeIterator for EscapeDefault {
 #[unstable(feature = "fused", issue = "35602")]
 impl FusedIterator for EscapeDefault {}
 
-#[stable(feature = "char_struct_display", since = "1.17.0")]
+#[stable(feature = "char_struct_display", since = "1.16.0")]
 impl fmt::Display for EscapeDefault {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         for c in self.clone() {
@@ -735,7 +735,7 @@ impl ExactSizeIterator for EscapeDebug { }
 #[unstable(feature = "fused", issue = "35602")]
 impl FusedIterator for EscapeDebug {}
 
-#[stable(feature = "char_struct_display", since = "1.17.0")]
+#[unstable(feature = "char_escape_debug", issue = "35068")]
 impl fmt::Display for EscapeDebug {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt::Display::fmt(&self.0, f)
diff --git a/src/libcore/convert.rs b/src/libcore/convert.rs
index abd686b15e2..4e170794c1d 100644
--- a/src/libcore/convert.rs
+++ b/src/libcore/convert.rs
@@ -225,7 +225,7 @@ pub trait TryFrom<T>: Sized {
     type Err;
 
     /// Performs the conversion.
-    fn try_from(T) -> Result<Self, Self::Err>;
+    fn try_from(value: T) -> Result<Self, Self::Err>;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/libcore/internal_macros.rs b/src/libcore/internal_macros.rs
index f2cdc9d6a98..9a7914064fd 100644
--- a/src/libcore/internal_macros.rs
+++ b/src/libcore/internal_macros.rs
@@ -13,7 +13,11 @@
 // based on "op T" where T is expected to be `Copy`able
 macro_rules! forward_ref_unop {
     (impl $imp:ident, $method:ident for $t:ty) => {
-        #[stable(feature = "rust1", since = "1.0.0")]
+        forward_ref_unop!(impl $imp, $method for $t,
+                #[stable(feature = "rust1", since = "1.0.0")]);
+    };
+    (impl $imp:ident, $method:ident for $t:ty, #[$attr:meta]) => {
+        #[$attr]
         impl<'a> $imp for &'a $t {
             type Output = <$t as $imp>::Output;
 
@@ -29,7 +33,11 @@ macro_rules! forward_ref_unop {
 // based on "T op U" where T and U are expected to be `Copy`able
 macro_rules! forward_ref_binop {
     (impl $imp:ident, $method:ident for $t:ty, $u:ty) => {
-        #[stable(feature = "rust1", since = "1.0.0")]
+        forward_ref_binop!(impl $imp, $method for $t, $u,
+                #[stable(feature = "rust1", since = "1.0.0")]);
+    };
+    (impl $imp:ident, $method:ident for $t:ty, $u:ty, #[$attr:meta]) => {
+        #[$attr]
         impl<'a> $imp<$u> for &'a $t {
             type Output = <$t as $imp<$u>>::Output;
 
@@ -39,7 +47,7 @@ macro_rules! forward_ref_binop {
             }
         }
 
-        #[stable(feature = "rust1", since = "1.0.0")]
+        #[$attr]
         impl<'a> $imp<&'a $u> for $t {
             type Output = <$t as $imp<$u>>::Output;
 
@@ -49,7 +57,7 @@ macro_rules! forward_ref_binop {
             }
         }
 
-        #[stable(feature = "rust1", since = "1.0.0")]
+        #[$attr]
         impl<'a, 'b> $imp<&'a $u> for &'b $t {
             type Output = <$t as $imp<$u>>::Output;
 
diff --git a/src/libcore/iter/mod.rs b/src/libcore/iter/mod.rs
index 3999db0d63c..d9b8c5ea589 100644
--- a/src/libcore/iter/mod.rs
+++ b/src/libcore/iter/mod.rs
@@ -1086,7 +1086,7 @@ impl<I: Iterator, P> Iterator for Filter<I, P> where P: FnMut(&I::Item) -> bool
 
     #[inline]
     fn next(&mut self) -> Option<I::Item> {
-        for x in self.iter.by_ref() {
+        for x in &mut self.iter {
             if (self.predicate)(&x) {
                 return Some(x);
             }
@@ -1099,6 +1099,26 @@ impl<I: Iterator, P> Iterator for Filter<I, P> where P: FnMut(&I::Item) -> bool
         let (_, upper) = self.iter.size_hint();
         (0, upper) // can't know a lower bound, due to the predicate
     }
+
+    // this special case allows the compiler to make `.filter(_).count()`
+    // branchless. Barring perfect branch prediction (which is unattainable in
+    // the general case), this will be much faster in >90% of cases (containing
+    // virtually all real workloads) and only a tiny bit slower in the rest.
+    //
+    // Having this specialization thus allows us to write `.filter(p).count()`
+    // where we would otherwise write `.map(|x| p(x) as usize).sum()`, which is
+    // less readable and also less backwards-compatible to Rust before 1.10.
+    //
+    // Using the branchless version will also simplify the LLVM byte code, thus
+    // leaving more budget for LLVM optimizations.
+    #[inline]
+    fn count(mut self) -> usize {
+        let mut count = 0;
+        for x in &mut self.iter {
+            count += (self.predicate)(&x) as usize;
+        }
+        count
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
index a86ceb9ac0d..cb180110d3c 100644
--- a/src/libcore/iter/traits.rs
+++ b/src/libcore/iter/traits.rs
@@ -661,29 +661,29 @@ pub trait Product<A = Self>: Sized {
 
 // NB: explicitly use Add and Mul here to inherit overflow checks
 macro_rules! integer_sum_product {
-    (@impls $zero:expr, $one:expr, $($a:ty)*) => ($(
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+    (@impls $zero:expr, $one:expr, #[$attr:meta], $($a:ty)*) => ($(
+        #[$attr]
         impl Sum for $a {
             fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
                 iter.fold($zero, Add::add)
             }
         }
 
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        #[$attr]
         impl Product for $a {
             fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
                 iter.fold($one, Mul::mul)
             }
         }
 
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        #[$attr]
         impl<'a> Sum<&'a $a> for $a {
             fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
                 iter.fold($zero, Add::add)
             }
         }
 
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        #[$attr]
         impl<'a> Product<&'a $a> for $a {
             fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
                 iter.fold($one, Mul::mul)
@@ -691,8 +691,12 @@ macro_rules! integer_sum_product {
         }
     )*);
     ($($a:ty)*) => (
-        integer_sum_product!(@impls 0, 1, $($a)+);
-        integer_sum_product!(@impls Wrapping(0), Wrapping(1), $(Wrapping<$a>)+);
+        integer_sum_product!(@impls 0, 1,
+                #[stable(feature = "iter_arith_traits", since = "1.12.0")],
+                $($a)+);
+        integer_sum_product!(@impls Wrapping(0), Wrapping(1),
+                #[stable(feature = "wrapping_iter_arith", since = "1.14.0")],
+                $(Wrapping<$a>)+);
     );
 }
 
diff --git a/src/libcore/num/int_macros.rs b/src/libcore/num/int_macros.rs
index 04311d687ea..3b1612a4ee2 100644
--- a/src/libcore/num/int_macros.rs
+++ b/src/libcore/num/int_macros.rs
@@ -12,12 +12,12 @@
 
 macro_rules! int_module {
     ($T:ident) => (int_module!($T, #[stable(feature = "rust1", since = "1.0.0")]););
-    ($T:ident, $($attr: tt)*) => (
+    ($T:ident, #[$attr:meta]) => (
         /// The smallest value that can be represented by this integer type.
-        $($attr)*
+        #[$attr]
         pub const MIN: $T = $T::min_value();
         /// The largest value that can be represented by this integer type.
-        $($attr)*
+        #[$attr]
         pub const MAX: $T = $T::max_value();
     )
 }
diff --git a/src/libcore/num/uint_macros.rs b/src/libcore/num/uint_macros.rs
index 2e59b39278a..f7e1f78d69e 100644
--- a/src/libcore/num/uint_macros.rs
+++ b/src/libcore/num/uint_macros.rs
@@ -12,12 +12,12 @@
 
 macro_rules! uint_module {
     ($T:ident) => (uint_module!($T, #[stable(feature = "rust1", since = "1.0.0")]););
-    ($T:ident, $($attr: tt)*) => (
+    ($T:ident, #[$attr:meta]) => (
         /// The smallest value that can be represented by this integer type.
-        $($attr)*
+        #[$attr]
         pub const MIN: $T = $T::min_value();
         /// The largest value that can be represented by this integer type.
-        $($attr)*
+        #[$attr]
         pub const MAX: $T = $T::max_value();
     )
 }
diff --git a/src/libcore/num/wrapping.rs b/src/libcore/num/wrapping.rs
index 50007c7d9b0..013f02685ba 100644
--- a/src/libcore/num/wrapping.rs
+++ b/src/libcore/num/wrapping.rs
@@ -131,7 +131,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0.wrapping_add(other.0))
             }
         }
-        forward_ref_binop! { impl Add, add for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl Add, add for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl AddAssign for Wrapping<$t> {
@@ -150,7 +151,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0.wrapping_sub(other.0))
             }
         }
-        forward_ref_binop! { impl Sub, sub for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl Sub, sub for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl SubAssign for Wrapping<$t> {
@@ -169,7 +171,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0.wrapping_mul(other.0))
             }
         }
-        forward_ref_binop! { impl Mul, mul for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl Mul, mul for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl MulAssign for Wrapping<$t> {
@@ -188,7 +191,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0.wrapping_div(other.0))
             }
         }
-        forward_ref_binop! { impl Div, div for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl Div, div for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl DivAssign for Wrapping<$t> {
@@ -207,7 +211,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0.wrapping_rem(other.0))
             }
         }
-        forward_ref_binop! { impl Rem, rem for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl Rem, rem for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl RemAssign for Wrapping<$t> {
@@ -226,7 +231,8 @@ macro_rules! wrapping_impl {
                 Wrapping(!self.0)
             }
         }
-        forward_ref_unop! { impl Not, not for Wrapping<$t> }
+        forward_ref_unop! { impl Not, not for Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "rust1", since = "1.0.0")]
         impl BitXor for Wrapping<$t> {
@@ -237,7 +243,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0 ^ other.0)
             }
         }
-        forward_ref_binop! { impl BitXor, bitxor for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl BitXor, bitxor for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl BitXorAssign for Wrapping<$t> {
@@ -256,7 +263,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0 | other.0)
             }
         }
-        forward_ref_binop! { impl BitOr, bitor for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl BitOr, bitor for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl BitOrAssign for Wrapping<$t> {
@@ -275,7 +283,8 @@ macro_rules! wrapping_impl {
                 Wrapping(self.0 & other.0)
             }
         }
-        forward_ref_binop! { impl BitAnd, bitand for Wrapping<$t>, Wrapping<$t> }
+        forward_ref_binop! { impl BitAnd, bitand for Wrapping<$t>, Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
 
         #[stable(feature = "op_assign_traits", since = "1.8.0")]
         impl BitAndAssign for Wrapping<$t> {
@@ -293,7 +302,8 @@ macro_rules! wrapping_impl {
                 Wrapping(0) - self
             }
         }
-        forward_ref_unop! { impl Neg, neg for Wrapping<$t> }
+        forward_ref_unop! { impl Neg, neg for Wrapping<$t>,
+                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
     )*)
 }
 
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index c4d7b2dcf96..9df8350d90f 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -633,6 +633,76 @@ impl<T> Option<T> {
     }
 
     /////////////////////////////////////////////////////////////////////////
+    // Entry-like operations to insert if None and return a reference
+    /////////////////////////////////////////////////////////////////////////
+
+    /// Inserts `v` into the option if it is `None`, then
+    /// returns a mutable reference to the contained value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(option_entry)]
+    ///
+    /// let mut x = None;
+    ///
+    /// {
+    ///     let y: &mut u32 = x.get_or_insert(5);
+    ///     assert_eq!(y, &5);
+    ///
+    ///     *y = 7;
+    /// }
+    ///
+    /// assert_eq!(x, Some(7));
+    /// ```
+    #[inline]
+    #[unstable(feature = "option_entry", issue = "39288")]
+    pub fn get_or_insert(&mut self, v: T) -> &mut T {
+        match *self {
+            None => *self = Some(v),
+            _ => (),
+        }
+
+        match *self {
+            Some(ref mut v) => v,
+            _ => unreachable!(),
+        }
+    }
+
+    /// Inserts a value computed from `f` into the option if it is `None`, then
+    /// returns a mutable reference to the contained value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(option_entry)]
+    ///
+    /// let mut x = None;
+    ///
+    /// {
+    ///     let y: &mut u32 = x.get_or_insert_with(|| 5);
+    ///     assert_eq!(y, &5);
+    ///
+    ///     *y = 7;
+    /// }
+    ///
+    /// assert_eq!(x, Some(7));
+    /// ```
+    #[inline]
+    #[unstable(feature = "option_entry", issue = "39288")]
+    pub fn get_or_insert_with<F: FnOnce() -> T>(&mut self, f: F) -> &mut T {
+        match *self {
+            None => *self = Some(f()),
+            _ => (),
+        }
+
+        match *self {
+            Some(ref mut v) => v,
+            _ => unreachable!(),
+        }
+    }
+
+    /////////////////////////////////////////////////////////////////////////
     // Misc
     /////////////////////////////////////////////////////////////////////////
 
diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index b942d85f980..1a482b75731 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -616,7 +616,7 @@ pub trait SliceIndex<T> {
     fn index_mut(self, slice: &mut [T]) -> &mut Self::Output;
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[stable(feature = "slice-get-slice-impls", since = "1.15.0")]
 impl<T> SliceIndex<T> for usize {
     type Output = T;
 
@@ -665,7 +665,7 @@ impl<T> SliceIndex<T> for usize {
     }
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[stable(feature = "slice-get-slice-impls", since = "1.15.0")]
 impl<T> SliceIndex<T> for  ops::Range<usize> {
     type Output = [T];
 
@@ -726,7 +726,7 @@ impl<T> SliceIndex<T> for  ops::Range<usize> {
     }
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[stable(feature = "slice-get-slice-impls", since = "1.15.0")]
 impl<T> SliceIndex<T> for ops::RangeTo<usize> {
     type Output = [T];
 
@@ -761,7 +761,7 @@ impl<T> SliceIndex<T> for ops::RangeTo<usize> {
     }
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[stable(feature = "slice-get-slice-impls", since = "1.15.0")]
 impl<T> SliceIndex<T> for ops::RangeFrom<usize> {
     type Output = [T];
 
@@ -796,7 +796,7 @@ impl<T> SliceIndex<T> for ops::RangeFrom<usize> {
     }
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[stable(feature = "slice-get-slice-impls", since = "1.15.0")]
 impl<T> SliceIndex<T> for ops::RangeFull {
     type Output = [T];
 
@@ -832,7 +832,7 @@ impl<T> SliceIndex<T> for ops::RangeFull {
 }
 
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
 impl<T> SliceIndex<T> for ops::RangeInclusive<usize> {
     type Output = [T];
 
@@ -895,7 +895,7 @@ impl<T> SliceIndex<T> for ops::RangeInclusive<usize> {
     }
 }
 
-#[stable(feature = "slice-get-slice-impls", since = "1.13.0")]
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
 impl<T> SliceIndex<T> for ops::RangeToInclusive<usize> {
     type Output = [T];
 
diff --git a/src/libcore/sync/atomic.rs b/src/libcore/sync/atomic.rs
index 743e3c41170..58cd0af7ee3 100644
--- a/src/libcore/sync/atomic.rs
+++ b/src/libcore/sync/atomic.rs
@@ -1318,6 +1318,24 @@ atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
     u64 AtomicU64 ATOMIC_U64_INIT
 }
+#[cfg(not(stage0))]
+#[cfg(target_has_atomic = "128")]
+atomic_int! {
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    i128 AtomicI128 ATOMIC_I128_INIT
+}
+#[cfg(not(stage0))]
+#[cfg(target_has_atomic = "128")]
+atomic_int! {
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    unstable(feature = "i128", issue = "35118"),
+    u128 AtomicU128 ATOMIC_U128_INIT
+}
 #[cfg(target_has_atomic = "ptr")]
 atomic_int!{
     stable(feature = "rust1", since = "1.0.0"),