Auto merge of #28200 - Manishearth:rollup, r=Manishearth

- Successful merges: #28164, #28170, #28184, #28186, #28187, #28188, #28191, #28193, #28194, #28195
- Failed merges: 

10 files changed, 82 insertions, 82 deletions

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index 06eb2227808..d37f5169af1 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -231,7 +231,7 @@ impl<T:Copy> Cell<T> {
     /// ```
     #[inline]
     #[unstable(feature = "as_unsafe_cell", issue = "27708")]
-    pub unsafe fn as_unsafe_cell<'a>(&'a self) -> &'a UnsafeCell<T> {
+    pub unsafe fn as_unsafe_cell(&self) -> &UnsafeCell<T> {
         &self.value
     }
 }
@@ -387,7 +387,7 @@ impl<T: ?Sized> RefCell<T> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
-    pub fn borrow<'a>(&'a self) -> Ref<'a, T> {
+    pub fn borrow(&self) -> Ref<T> {
         match BorrowRef::new(&self.borrow) {
             Some(b) => Ref {
                 _value: unsafe { &*self.value.get() },
@@ -433,7 +433,7 @@ impl<T: ?Sized> RefCell<T> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
-    pub fn borrow_mut<'a>(&'a self) -> RefMut<'a, T> {
+    pub fn borrow_mut(&self) -> RefMut<T> {
         match BorrowRefMut::new(&self.borrow) {
             Some(b) => RefMut {
                 _value: unsafe { &mut *self.value.get() },
@@ -450,7 +450,7 @@ impl<T: ?Sized> RefCell<T> {
     /// This function is `unsafe` because `UnsafeCell`'s field is public.
     #[inline]
     #[unstable(feature = "as_unsafe_cell", issue = "27708")]
-    pub unsafe fn as_unsafe_cell<'a>(&'a self) -> &'a UnsafeCell<T> {
+    pub unsafe fn as_unsafe_cell(&self) -> &UnsafeCell<T> {
         &self.value
     }
 }
@@ -541,7 +541,7 @@ impl<'b, T: ?Sized> Deref for Ref<'b, T> {
     type Target = T;
 
     #[inline]
-    fn deref<'a>(&'a self) -> &'a T {
+    fn deref(&self) -> &T {
         self._value
     }
 }
@@ -750,7 +750,7 @@ impl<'b, T: ?Sized> Deref for RefMut<'b, T> {
     type Target = T;
 
     #[inline]
-    fn deref<'a>(&'a self) -> &'a T {
+    fn deref(&self) -> &T {
         self._value
     }
 }
@@ -758,7 +758,7 @@ impl<'b, T: ?Sized> Deref for RefMut<'b, T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'b, T: ?Sized> DerefMut for RefMut<'b, T> {
     #[inline]
-    fn deref_mut<'a>(&'a mut self) -> &'a mut T {
+    fn deref_mut(&mut self) -> &mut T {
         self._value
     }
 }
diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index 3d17b10ba3a..97dcb2475a3 100644
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -1513,7 +1513,7 @@ impl<A, B> Iterator for Chain<A, B> where
     fn next(&mut self) -> Option<A::Item> {
         match self.state {
             ChainState::Both => match self.a.next() {
-                elt @ Some(..) => return elt,
+                elt @ Some(..) => elt,
                 None => {
                     self.state = ChainState::Back;
                     self.b.next()
@@ -1590,7 +1590,7 @@ impl<A, B> DoubleEndedIterator for Chain<A, B> where
     fn next_back(&mut self) -> Option<A::Item> {
         match self.state {
             ChainState::Both => match self.b.next_back() {
-                elt @ Some(..) => return elt,
+                elt @ Some(..) => elt,
                 None => {
                     self.state = ChainState::Front;
                     self.a.next_back()
@@ -1683,7 +1683,7 @@ impl<B, I: Iterator, F> Iterator for Map<I, F> where F: FnMut(I::Item) -> B {
 
     #[inline]
     fn next(&mut self) -> Option<B> {
-        self.iter.next().map(|a| (self.f)(a))
+        self.iter.next().map(&mut self.f)
     }
 
     #[inline]
@@ -1698,7 +1698,7 @@ impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for Map<I, F> where
 {
     #[inline]
     fn next_back(&mut self) -> Option<B> {
-        self.iter.next_back().map(|a| (self.f)(a))
+        self.iter.next_back().map(&mut self.f)
     }
 }
 
@@ -2210,7 +2210,7 @@ impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F>
                     return Some(x)
                 }
             }
-            match self.iter.next().map(|x| (self.f)(x)) {
+            match self.iter.next().map(&mut self.f) {
                 None => return self.backiter.as_mut().and_then(|it| it.next()),
                 next => self.frontiter = next.map(IntoIterator::into_iter),
             }
@@ -2243,7 +2243,7 @@ impl<I: DoubleEndedIterator, U, F> DoubleEndedIterator for FlatMap<I, U, F> wher
                     return Some(y)
                 }
             }
-            match self.iter.next_back().map(|x| (self.f)(x)) {
+            match self.iter.next_back().map(&mut self.f) {
                 None => return self.frontiter.as_mut().and_then(|it| it.next_back()),
                 next => self.backiter = next.map(IntoIterator::into_iter),
             }
diff --git a/src/libcore/nonzero.rs b/src/libcore/nonzero.rs
index 2524e5662aa..c945e4e0661 100644
--- a/src/libcore/nonzero.rs
+++ b/src/libcore/nonzero.rs
@@ -51,7 +51,7 @@ impl<T: Zeroable> Deref for NonZero<T> {
     type Target = T;
 
     #[inline]
-    fn deref<'a>(&'a self) -> &'a T {
+    fn deref(&self) -> &T {
         let NonZero(ref inner) = *self;
         inner
     }
diff --git a/src/libcore/num/flt2dec/bignum.rs b/src/libcore/num/flt2dec/bignum.rs
index ee2ffbffab6..091e9c889da 100644
--- a/src/libcore/num/flt2dec/bignum.rs
+++ b/src/libcore/num/flt2dec/bignum.rs
@@ -211,7 +211,7 @@ macro_rules! define_bignum {
                 self
             }
 
-            pub fn add_small<'a>(&'a mut self, other: $ty) -> &'a mut $name {
+            pub fn add_small(&mut self, other: $ty) -> &mut $name {
                 use num::flt2dec::bignum::FullOps;
 
                 let (mut carry, v) = self.base[0].full_add(other, false);
@@ -248,7 +248,7 @@ macro_rules! define_bignum {
 
             /// Multiplies itself by a digit-sized `other` and returns its own
             /// mutable reference.
-            pub fn mul_small<'a>(&'a mut self, other: $ty) -> &'a mut $name {
+            pub fn mul_small(&mut self, other: $ty) -> &mut $name {
                 use num::flt2dec::bignum::FullOps;
 
                 let mut sz = self.size;
@@ -267,7 +267,7 @@ macro_rules! define_bignum {
             }
 
             /// Multiplies itself by `2^bits` and returns its own mutable reference.
-            pub fn mul_pow2<'a>(&'a mut self, bits: usize) -> &'a mut $name {
+            pub fn mul_pow2(&mut self, bits: usize) -> &mut $name {
                 use mem;
 
                 let digitbits = mem::size_of::<$ty>() * 8;
@@ -308,7 +308,7 @@ macro_rules! define_bignum {
             }
 
             /// Multiplies itself by `5^e` and returns its own mutable reference.
-            pub fn mul_pow5<'a>(&'a mut self, mut e: usize) -> &'a mut $name {
+            pub fn mul_pow5(&mut self, mut e: usize) -> &mut $name {
                 use mem;
                 use num::flt2dec::bignum::SMALL_POW5;
 
@@ -377,7 +377,7 @@ macro_rules! define_bignum {
 
             /// Divides itself by a digit-sized `other` and returns its own
             /// mutable reference *and* the remainder.
-            pub fn div_rem_small<'a>(&'a mut self, other: $ty) -> (&'a mut $name, $ty) {
+            pub fn div_rem_small(&mut self, other: $ty) -> (&mut $name, $ty) {
                 use num::flt2dec::bignum::FullOps;
 
                 assert!(other > 0);
diff --git a/src/libcore/num/flt2dec/strategy/dragon.rs b/src/libcore/num/flt2dec/strategy/dragon.rs
index ab610f28e9e..40aa2a527db 100644
--- a/src/libcore/num/flt2dec/strategy/dragon.rs
+++ b/src/libcore/num/flt2dec/strategy/dragon.rs
@@ -42,7 +42,7 @@ static POW10TO256: [Digit; 27] =
      0xcc5573c0, 0x65f9ef17, 0x55bc28f2, 0x80dcc7f7, 0xf46eeddc, 0x5fdcefce, 0x553f7];
 
 #[doc(hidden)]
-pub fn mul_pow10<'a>(x: &'a mut Big, n: usize) -> &'a mut Big {
+pub fn mul_pow10(x: &mut Big, n: usize) -> &mut Big {
     debug_assert!(n < 512);
     if n &   7 != 0 { x.mul_small(POW10[n & 7]); }
     if n &   8 != 0 { x.mul_small(POW10[8]); }
@@ -54,7 +54,7 @@ pub fn mul_pow10<'a>(x: &'a mut Big, n: usize) -> &'a mut Big {
     x
 }
 
-fn div_2pow10<'a>(x: &'a mut Big, mut n: usize) -> &'a mut Big {
+fn div_2pow10(x: &mut Big, mut n: usize) -> &mut Big {
     let largest = POW10.len() - 1;
     while n > largest {
         x.div_rem_small(POW10[largest]);
diff --git a/src/libcore/ops.rs b/src/libcore/ops.rs
index 3fb720ab6c8..07de4d0761b 100644
--- a/src/libcore/ops.rs
+++ b/src/libcore/ops.rs
@@ -965,7 +965,7 @@ pub trait Index<Idx: ?Sized> {
 
     /// The method for the indexing (`Foo[Bar]`) operation
     #[stable(feature = "rust1", since = "1.0.0")]
-    fn index<'a>(&'a self, index: Idx) -> &'a Self::Output;
+    fn index(&self, index: Idx) -> &Self::Output;
 }
 
 /// The `IndexMut` trait is used to specify the functionality of indexing
@@ -1008,7 +1008,7 @@ pub trait Index<Idx: ?Sized> {
 pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
     /// The method for the indexing (`Foo[Bar]`) operation
     #[stable(feature = "rust1", since = "1.0.0")]
-    fn index_mut<'a>(&'a mut self, index: Idx) -> &'a mut Self::Output;
+    fn index_mut(&mut self, index: Idx) -> &mut Self::Output;
 }
 
 /// An unbounded range.
@@ -1119,7 +1119,7 @@ pub trait Deref {
 
     /// The method called to dereference a value
     #[stable(feature = "rust1", since = "1.0.0")]
-    fn deref<'a>(&'a self) -> &'a Self::Target;
+    fn deref(&self) -> &Self::Target;
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1180,7 +1180,7 @@ impl<'a, T: ?Sized> Deref for &'a mut T {
 pub trait DerefMut: Deref {
     /// The method called to mutably dereference a value
     #[stable(feature = "rust1", since = "1.0.0")]
-    fn deref_mut<'a>(&'a mut self) -> &'a mut Self::Target;
+    fn deref_mut(&mut self) -> &mut Self::Target;
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index a36a120689c..1434617badd 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -241,7 +241,7 @@ impl<T> Option<T> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn as_ref<'r>(&'r self) -> Option<&'r T> {
+    pub fn as_ref(&self) -> Option<&T> {
         match *self {
             Some(ref x) => Some(x),
             None => None,
@@ -262,7 +262,7 @@ impl<T> Option<T> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn as_mut<'r>(&'r mut self) -> Option<&'r mut T> {
+    pub fn as_mut(&mut self) -> Option<&mut T> {
         match *self {
             Some(ref mut x) => Some(x),
             None => None,
@@ -289,7 +289,7 @@ impl<T> Option<T> {
     #[unstable(feature = "as_slice",
                reason = "waiting for mut conventions",
                issue = "27776")]
-    pub fn as_mut_slice<'r>(&'r mut self) -> &'r mut [T] {
+    pub fn as_mut_slice(&mut self) -> &mut [T] {
         match *self {
             Some(ref mut x) => {
                 let result: &mut [T] = slice::mut_ref_slice(x);
@@ -692,7 +692,7 @@ impl<T> Option<T> {
     #[inline]
     #[unstable(feature = "as_slice", since = "unsure of the utility here",
                issue = "27776")]
-    pub fn as_slice<'a>(&'a self) -> &'a [T] {
+    pub fn as_slice(&self) -> &[T] {
         match *self {
             Some(ref x) => slice::ref_slice(x),
             None => {
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index b7479b0c604..83bdaf0923e 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -51,7 +51,7 @@ pub use intrinsics::write_bytes;
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn null<T>() -> *const T { 0 as *const T }
+pub const fn null<T>() -> *const T { 0 as *const T }
 
 /// Creates a null mutable raw pointer.
 ///
@@ -65,7 +65,7 @@ pub fn null<T>() -> *const T { 0 as *const T }
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn null_mut<T>() -> *mut T { 0 as *mut T }
+pub const fn null_mut<T>() -> *mut T { 0 as *mut T }
 
 /// Swaps the values at two mutable locations of the same type, without
 /// deinitialising either. They may overlap, unlike `mem::swap` which is
@@ -163,7 +163,7 @@ impl<T: ?Sized> *const T {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_null(self) -> bool where T: Sized {
-        self == 0 as *const T
+        self == null()
     }
 
     /// Returns `None` if the pointer is null, or else returns a reference to
@@ -212,7 +212,7 @@ impl<T: ?Sized> *mut T {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is_null(self) -> bool where T: Sized {
-        self == 0 as *mut T
+        self == null_mut()
     }
 
     /// Returns `None` if the pointer is null, or else returns a reference to
@@ -468,7 +468,7 @@ impl<T:?Sized> Deref for Unique<T> {
     type Target = *mut T;
 
     #[inline]
-    fn deref<'a>(&'a self) -> &'a *mut T {
+    fn deref(&self) -> &*mut T {
         unsafe { mem::transmute(&*self.pointer) }
     }
 }
diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index fdd5e61c8f2..cf605f507bc 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -69,48 +69,48 @@ use raw::Slice as RawSlice;
 pub trait SliceExt {
     type Item;
 
-    fn split_at<'a>(&'a self, mid: usize) -> (&'a [Self::Item], &'a [Self::Item]);
-    fn iter<'a>(&'a self) -> Iter<'a, Self::Item>;
-    fn split<'a, P>(&'a self, pred: P) -> Split<'a, Self::Item, P>
+    fn split_at(&self, mid: usize) -> (&[Self::Item], &[Self::Item]);
+    fn iter(&self) -> Iter<Self::Item>;
+    fn split<P>(&self, pred: P) -> Split<Self::Item, P>
                     where P: FnMut(&Self::Item) -> bool;
-    fn splitn<'a, P>(&'a self, n: usize, pred: P) -> SplitN<'a, Self::Item, P>
+    fn splitn<P>(&self, n: usize, pred: P) -> SplitN<Self::Item, P>
                      where P: FnMut(&Self::Item) -> bool;
-    fn rsplitn<'a, P>(&'a self,  n: usize, pred: P) -> RSplitN<'a, Self::Item, P>
+    fn rsplitn<P>(&self,  n: usize, pred: P) -> RSplitN<Self::Item, P>
                       where P: FnMut(&Self::Item) -> bool;
-    fn windows<'a>(&'a self, size: usize) -> Windows<'a, Self::Item>;
-    fn chunks<'a>(&'a self, size: usize) -> Chunks<'a, Self::Item>;
-    fn get<'a>(&'a self, index: usize) -> Option<&'a Self::Item>;
-    fn first<'a>(&'a self) -> Option<&'a Self::Item>;
-    fn tail<'a>(&'a self) -> &'a [Self::Item];
-    fn init<'a>(&'a self) -> &'a [Self::Item];
-    fn split_first<'a>(&'a self) -> Option<(&'a Self::Item, &'a [Self::Item])>;
-    fn split_last<'a>(&'a self) -> Option<(&'a Self::Item, &'a [Self::Item])>;
-    fn last<'a>(&'a self) -> Option<&'a Self::Item>;
-    unsafe fn get_unchecked<'a>(&'a self, index: usize) -> &'a Self::Item;
+    fn windows(&self, size: usize) -> Windows<Self::Item>;
+    fn chunks(&self, size: usize) -> Chunks<Self::Item>;
+    fn get(&self, index: usize) -> Option<&Self::Item>;
+    fn first(&self) -> Option<&Self::Item>;
+    fn tail(&self) -> &[Self::Item];
+    fn init(&self) -> &[Self::Item];
+    fn split_first(&self) -> Option<(&Self::Item, &[Self::Item])>;
+    fn split_last(&self) -> Option<(&Self::Item, &[Self::Item])>;
+    fn last(&self) -> Option<&Self::Item>;
+    unsafe fn get_unchecked(&self, index: usize) -> &Self::Item;
     fn as_ptr(&self) -> *const Self::Item;
     fn binary_search_by<F>(&self, f: F) -> Result<usize, usize> where
         F: FnMut(&Self::Item) -> Ordering;
     fn len(&self) -> usize;
     fn is_empty(&self) -> bool { self.len() == 0 }
-    fn get_mut<'a>(&'a mut self, index: usize) -> Option<&'a mut Self::Item>;
-    fn iter_mut<'a>(&'a mut self) -> IterMut<'a, Self::Item>;
-    fn first_mut<'a>(&'a mut self) -> Option<&'a mut Self::Item>;
-    fn tail_mut<'a>(&'a mut self) -> &'a mut [Self::Item];
-    fn init_mut<'a>(&'a mut self) -> &'a mut [Self::Item];
-    fn split_first_mut<'a>(&'a mut self) -> Option<(&'a mut Self::Item, &'a mut [Self::Item])>;
-    fn split_last_mut<'a>(&'a mut self) -> Option<(&'a mut Self::Item, &'a mut [Self::Item])>;
-    fn last_mut<'a>(&'a mut self) -> Option<&'a mut Self::Item>;
-    fn split_mut<'a, P>(&'a mut self, pred: P) -> SplitMut<'a, Self::Item, P>
+    fn get_mut(&mut self, index: usize) -> Option<&mut Self::Item>;
+    fn iter_mut(&mut self) -> IterMut<Self::Item>;
+    fn first_mut(&mut self) -> Option<&mut Self::Item>;
+    fn tail_mut(&mut self) -> &mut [Self::Item];
+    fn init_mut(&mut self) -> &mut [Self::Item];
+    fn split_first_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>;
+    fn split_last_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>;
+    fn last_mut(&mut self) -> Option<&mut Self::Item>;
+    fn split_mut<P>(&mut self, pred: P) -> SplitMut<Self::Item, P>
                         where P: FnMut(&Self::Item) -> bool;
     fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<Self::Item, P>
                      where P: FnMut(&Self::Item) -> bool;
     fn rsplitn_mut<P>(&mut self,  n: usize, pred: P) -> RSplitNMut<Self::Item, P>
                       where P: FnMut(&Self::Item) -> bool;
-    fn chunks_mut<'a>(&'a mut self, chunk_size: usize) -> ChunksMut<'a, Self::Item>;
+    fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<Self::Item>;
     fn swap(&mut self, a: usize, b: usize);
-    fn split_at_mut<'a>(&'a mut self, mid: usize) -> (&'a mut [Self::Item], &'a mut [Self::Item]);
+    fn split_at_mut(&mut self, mid: usize) -> (&mut [Self::Item], &mut [Self::Item]);
     fn reverse(&mut self);
-    unsafe fn get_unchecked_mut<'a>(&'a mut self, index: usize) -> &'a mut Self::Item;
+    unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut Self::Item;
     fn as_mut_ptr(&mut self) -> *mut Self::Item;
 
     fn position_elem(&self, t: &Self::Item) -> Option<usize> where Self::Item: PartialEq;
@@ -163,7 +163,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn iter<'a>(&'a self) -> Iter<'a, T> {
+    fn iter(&self) -> Iter<T> {
         unsafe {
             let p = if mem::size_of::<T>() == 0 {
                 1 as *const _
@@ -182,7 +182,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn split<'a, P>(&'a self, pred: P) -> Split<'a, T, P> where P: FnMut(&T) -> bool {
+    fn split<P>(&self, pred: P) -> Split<T, P> where P: FnMut(&T) -> bool {
         Split {
             v: self,
             pred: pred,
@@ -191,7 +191,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn splitn<'a, P>(&'a self, n: usize, pred: P) -> SplitN<'a, T, P> where
+    fn splitn<P>(&self, n: usize, pred: P) -> SplitN<T, P> where
         P: FnMut(&T) -> bool,
     {
         SplitN {
@@ -204,7 +204,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn rsplitn<'a, P>(&'a self, n: usize, pred: P) -> RSplitN<'a, T, P> where
+    fn rsplitn<P>(&self, n: usize, pred: P) -> RSplitN<T, P> where
         P: FnMut(&T) -> bool,
     {
         RSplitN {
@@ -311,7 +311,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn iter_mut<'a>(&'a mut self) -> IterMut<'a, T> {
+    fn iter_mut(&mut self) -> IterMut<T> {
         unsafe {
             let p = if mem::size_of::<T>() == 0 {
                 1 as *mut _
@@ -368,12 +368,12 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn split_mut<'a, P>(&'a mut self, pred: P) -> SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
+    fn split_mut<P>(&mut self, pred: P) -> SplitMut<T, P> where P: FnMut(&T) -> bool {
         SplitMut { v: self, pred: pred, finished: false }
     }
 
     #[inline]
-    fn splitn_mut<'a, P>(&'a mut self, n: usize, pred: P) -> SplitNMut<'a, T, P> where
+    fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<T, P> where
         P: FnMut(&T) -> bool
     {
         SplitNMut {
@@ -386,7 +386,7 @@ impl<T> SliceExt for [T] {
     }
 
     #[inline]
-    fn rsplitn_mut<'a, P>(&'a mut self, n: usize, pred: P) -> RSplitNMut<'a, T, P> where
+    fn rsplitn_mut<P>(&mut self, n: usize, pred: P) -> RSplitNMut<T, P> where
         P: FnMut(&T) -> bool,
     {
         RSplitNMut {
@@ -1410,7 +1410,7 @@ impl<'a, T> ExactSizeIterator for ChunksMut<'a, T> {}
 
 /// Converts a pointer to A into a slice of length 1 (without copying).
 #[unstable(feature = "ref_slice", issue = "27774")]
-pub fn ref_slice<'a, A>(s: &'a A) -> &'a [A] {
+pub fn ref_slice<A>(s: &A) -> &[A] {
     unsafe {
         from_raw_parts(s, 1)
     }
@@ -1418,7 +1418,7 @@ pub fn ref_slice<'a, A>(s: &'a A) -> &'a [A] {
 
 /// Converts a pointer to A into a slice of length 1 (without copying).
 #[unstable(feature = "ref_slice", issue = "27774")]
-pub fn mut_ref_slice<'a, A>(s: &'a mut A) -> &'a mut [A] {
+pub fn mut_ref_slice<A>(s: &mut A) -> &mut [A] {
     unsafe {
         from_raw_parts_mut(s, 1)
     }
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 7d32f61b3dd..4612fc89008 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -142,7 +142,7 @@ pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
 /// that the string contains valid UTF-8.
 #[inline(always)]
 #[stable(feature = "rust1", since = "1.0.0")]
-pub unsafe fn from_utf8_unchecked<'a>(v: &'a [u8]) -> &'a str {
+pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
     mem::transmute(v)
 }
 
@@ -1270,9 +1270,9 @@ pub trait StrExt {
 
     fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
     fn contains_char<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
-    fn chars<'a>(&'a self) -> Chars<'a>;
-    fn bytes<'a>(&'a self) -> Bytes<'a>;
-    fn char_indices<'a>(&'a self) -> CharIndices<'a>;
+    fn chars(&self) -> Chars;
+    fn bytes(&self) -> Bytes;
+    fn char_indices(&self) -> CharIndices;
     fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P>;
     fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
         where P::Searcher: ReverseSearcher<'a>;
@@ -1288,12 +1288,12 @@ pub trait StrExt {
     fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P>;
     fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P>
         where P::Searcher: ReverseSearcher<'a>;
-    fn lines<'a>(&'a self) -> Lines<'a>;
-    fn lines_any<'a>(&'a self) -> LinesAny<'a>;
+    fn lines(&self) -> Lines;
+    fn lines_any(&self) -> LinesAny;
     fn char_len(&self) -> usize;
-    fn slice_chars<'a>(&'a self, begin: usize, end: usize) -> &'a str;
-    unsafe fn slice_unchecked<'a>(&'a self, begin: usize, end: usize) -> &'a str;
-    unsafe fn slice_mut_unchecked<'a>(&'a mut self, begin: usize, end: usize) -> &'a mut str;
+    fn slice_chars(&self, begin: usize, end: usize) -> &str;
+    unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str;
+    unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str;
     fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
     fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
         where P::Searcher: ReverseSearcher<'a>;
@@ -1307,14 +1307,14 @@ pub trait StrExt {
     fn char_range_at_reverse(&self, start: usize) -> CharRange;
     fn char_at(&self, i: usize) -> char;
     fn char_at_reverse(&self, i: usize) -> char;
-    fn as_bytes<'a>(&'a self) -> &'a [u8];
+    fn as_bytes(&self) -> &[u8];
     fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
     fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
         where P::Searcher: ReverseSearcher<'a>;
     fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
     fn split_at(&self, mid: usize) -> (&str, &str);
     fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str);
-    fn slice_shift_char<'a>(&'a self) -> Option<(char, &'a str)>;
+    fn slice_shift_char(&self) -> Option<(char, &str)>;
     fn subslice_offset(&self, inner: &str) -> usize;
     fn as_ptr(&self) -> *const u8;
     fn len(&self) -> usize;