Remove usage of .map(|&foo| foo)

Author: Ryman

src/libcore/iter.rs

@@ -540,7 +540,7 @@ pub trait IteratorExt: Iterator + Sized {
     ///
     /// let a = [1, 4, 2, 3, 8, 9, 6];
     /// let sum = a.iter()
-    ///             .map(|&x| x)
+    ///             .cloned()
     ///             .inspect(|&x| println!("filtering {}", x))
     ///             .filter(|&x| x % 2 == 0)
     ///             .inspect(|&x| println!("{} made it through", x))
@@ -579,7 +579,7 @@ pub trait IteratorExt: Iterator + Sized {
     ///
     /// ```
     /// let a = [1, 2, 3, 4, 5];
-    /// let b: Vec<_> = a.iter().map(|&x| x).collect();
+    /// let b: Vec<_> = a.iter().cloned().collect();
     /// assert_eq!(a, b);
     /// ```
     #[inline]
@@ -955,7 +955,7 @@ pub trait IteratorExt: Iterator + Sized {
     ///
     /// ```
     /// let a = [(1, 2), (3, 4)];
-    /// let (left, right): (Vec<_>, Vec<_>) = a.iter().map(|&x| x).unzip();
+    /// let (left, right): (Vec<_>, Vec<_>) = a.iter().cloned().unzip();
     /// assert_eq!([1, 3], left);
     /// assert_eq!([2, 4], right);
     /// ```
@@ -1160,7 +1160,7 @@ pub trait AdditiveIterator<A> {
     /// use std::iter::AdditiveIterator;
     ///
     /// let a = [1i32, 2, 3, 4, 5];
-    /// let mut it = a.iter().map(|&x| x);
+    /// let mut it = a.iter().cloned();
     /// assert!(it.sum() == 15);
     /// ```
     fn sum(self) -> A;

src/libcoretest/iter.rs

@@ -91,7 +91,7 @@ fn test_iterator_chain() {
     assert_eq!(i, expected.len());
 
     let ys = count(30, 10).take(4);
-    let mut it = xs.iter().map(|&x| x).chain(ys);
+    let mut it = xs.iter().cloned().chain(ys);
     let mut i = 0;
     for x in it {
         assert_eq!(x, expected[i]);
@@ -119,7 +119,7 @@ fn test_iterator_enumerate() {
 #[test]
 fn test_iterator_peekable() {
     let xs = vec![0, 1, 2, 3, 4, 5];
-    let mut it = xs.iter().map(|&x|x).peekable();
+    let mut it = xs.iter().cloned().peekable();
 
     assert_eq!(it.len(), 6);
     assert_eq!(it.peek().unwrap(), &0);
@@ -259,7 +259,7 @@ fn test_inspect() {
     let mut n = 0;
 
     let ys = xs.iter()
-               .map(|&x| x)
+               .cloned()
                .inspect(|_| n += 1)
                .collect::<Vec<uint>>();
 
@@ -329,33 +329,33 @@ fn test_iterator_len() {
 #[test]
 fn test_iterator_sum() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-    assert_eq!(v[..4].iter().map(|&x| x).sum(), 6);
-    assert_eq!(v.iter().map(|&x| x).sum(), 55);
-    assert_eq!(v[..0].iter().map(|&x| x).sum(), 0);
+    assert_eq!(v[..4].iter().cloned().sum(), 6);
+    assert_eq!(v.iter().cloned().sum(), 55);
+    assert_eq!(v[..0].iter().cloned().sum(), 0);
 }
 
 #[test]
 fn test_iterator_product() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-    assert_eq!(v[..4].iter().map(|&x| x).product(), 0);
-    assert_eq!(v[1..5].iter().map(|&x| x).product(), 24);
-    assert_eq!(v[..0].iter().map(|&x| x).product(), 1);
+    assert_eq!(v[..4].iter().cloned().product(), 0);
+    assert_eq!(v[1..5].iter().cloned().product(), 24);
+    assert_eq!(v[..0].iter().cloned().product(), 1);
 }
 
 #[test]
 fn test_iterator_max() {
     let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-    assert_eq!(v[..4].iter().map(|&x| x).max(), Some(3));
-    assert_eq!(v.iter().map(|&x| x).max(), Some(10));
-    assert_eq!(v[..0].iter().map(|&x| x).max(), None);
+    assert_eq!(v[..4].iter().cloned().max(), Some(3));
+    assert_eq!(v.iter().cloned().max(), Some(10));
+    assert_eq!(v[..0].iter().cloned().max(), None);
 }
 
 #[test]
 fn test_iterator_min() {
     let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-    assert_eq!(v[..4].iter().map(|&x| x).min(), Some(0));
-    assert_eq!(v.iter().map(|&x| x).min(), Some(0));
-    assert_eq!(v[..0].iter().map(|&x| x).min(), None);
+    assert_eq!(v[..4].iter().cloned().min(), Some(0));
+    assert_eq!(v.iter().cloned().min(), Some(0));
+    assert_eq!(v[..0].iter().cloned().min(), None);
 }
 
 #[test]
@@ -373,7 +373,7 @@ fn test_iterator_size_hint() {
     assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
     assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
     assert_eq!(c.clone().enumerate().size_hint(), (uint::MAX, None));
-    assert_eq!(c.clone().chain(vi.clone().map(|&i| i)).size_hint(), (uint::MAX, None));
+    assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (uint::MAX, None));
     assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
     assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
     assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
@@ -398,7 +398,7 @@ fn test_iterator_size_hint() {
 #[test]
 fn test_collect() {
     let a = vec![1, 2, 3, 4, 5];
-    let b: Vec<int> = a.iter().map(|&x| x).collect();
+    let b: Vec<int> = a.iter().cloned().collect();
     assert!(a == b);
 }
 
@@ -471,7 +471,7 @@ fn test_rev() {
     let mut it = xs.iter();
     it.next();
     it.next();
-    assert!(it.rev().map(|&x| x).collect::<Vec<int>>() ==
+    assert!(it.rev().cloned().collect::<Vec<int>>() ==
             vec![16, 14, 12, 10, 8, 6]);
 }
 
@@ -508,7 +508,7 @@ fn test_double_ended_map() {
 #[test]
 fn test_double_ended_enumerate() {
     let xs = [1, 2, 3, 4, 5, 6];
-    let mut it = xs.iter().map(|&x| x).enumerate();
+    let mut it = xs.iter().cloned().enumerate();
     assert_eq!(it.next(), Some((0, 1)));
     assert_eq!(it.next(), Some((1, 2)));
     assert_eq!(it.next_back(), Some((5, 6)));
@@ -522,8 +522,8 @@ fn test_double_ended_enumerate() {
 fn test_double_ended_zip() {
     let xs = [1, 2, 3, 4, 5, 6];
     let ys = [1, 2, 3, 7];
-    let a = xs.iter().map(|&x| x);
-    let b = ys.iter().map(|&x| x);
+    let a = xs.iter().cloned();
+    let b = ys.iter().cloned();
     let mut it = a.zip(b);
     assert_eq!(it.next(), Some((1, 1)));
     assert_eq!(it.next(), Some((2, 2)));

src/librand/isaac.rs

@@ -215,7 +215,7 @@ impl<'a> SeedableRng<&'a [u32]> for IsaacRng {
     fn reseed(&mut self, seed: &'a [u32]) {
         // make the seed into [seed[0], seed[1], ..., seed[seed.len()
         // - 1], 0, 0, ...], to fill rng.rsl.
-        let seed_iter = seed.iter().map(|&x| x).chain(repeat(0u32));
+        let seed_iter = seed.iter().cloned().chain(repeat(0u32));
 
         for (rsl_elem, seed_elem) in self.rsl.iter_mut().zip(seed_iter) {
             *rsl_elem = seed_elem;
@@ -458,7 +458,7 @@ impl<'a> SeedableRng<&'a [u64]> for Isaac64Rng {
     fn reseed(&mut self, seed: &'a [u64]) {
         // make the seed into [seed[0], seed[1], ..., seed[seed.len()
         // - 1], 0, 0, ...], to fill rng.rsl.
-        let seed_iter = seed.iter().map(|&x| x).chain(repeat(0u64));
+        let seed_iter = seed.iter().cloned().chain(repeat(0u64));
 
         for (rsl_elem, seed_elem) in self.rsl.iter_mut().zip(seed_iter) {
             *rsl_elem = seed_elem;

src/librustc/middle/dataflow.rs

@@ -89,7 +89,7 @@ struct PropagationContext<'a, 'b: 'a, 'tcx: 'b, O: 'a> {
 }
 
 fn to_cfgidx_or_die(id: ast::NodeId, index: &NodeMap<CFGIndex>) -> CFGIndex {
-    let opt_cfgindex = index.get(&id).map(|&i|i);
+    let opt_cfgindex = index.get(&id).cloned();
     opt_cfgindex.unwrap_or_else(|| {
         panic!("nodeid_to_index does not have entry for NodeId {}", id);
     })
@@ -400,7 +400,7 @@ impl<'a, 'tcx, O:DataFlowOperator> DataFlowContext<'a, 'tcx, O> {
 
             let mut changed = false;
             for &node_id in &edge.data.exiting_scopes {
-                let opt_cfg_idx = self.nodeid_to_index.get(&node_id).map(|&i|i);
+                let opt_cfg_idx = self.nodeid_to_index.get(&node_id).cloned();
                 match opt_cfg_idx {
                     Some(cfg_idx) => {
                         let (start, end) = self.compute_id_range(cfg_idx);

src/librustc/middle/subst.rs

@@ -113,7 +113,7 @@ impl<'tcx> Substs<'tcx> {
     }
 
     pub fn self_ty(&self) -> Option<Ty<'tcx>> {
-        self.types.get_self().map(|&t| t)
+        self.types.get_self().cloned()
     }
 
     pub fn with_self_ty(&self, self_ty: Ty<'tcx>) -> Substs<'tcx> {

src/librustc/middle/traits/object_safety.rs

@@ -57,7 +57,7 @@ pub fn is_object_safe<'tcx>(tcx: &ty::ctxt<'tcx>,
 {
     // Because we query yes/no results frequently, we keep a cache:
     let cached_result =
-        tcx.object_safety_cache.borrow().get(&trait_ref.def_id()).map(|&r| r);
+        tcx.object_safety_cache.borrow().get(&trait_ref.def_id()).cloned();
 
     let result =
         cached_result.unwrap_or_else(|| {

src/librustc/middle/traits/select.rs

@@ -1581,7 +1581,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     ty::substd_enum_variants(self.tcx(), def_id, substs)
                     .iter()
                     .flat_map(|variant| variant.args.iter())
-                    .map(|&ty| ty)
+                    .cloned()
                     .collect();
                 nominal(self, bound, def_id, types)
             }

src/librustc/middle/ty.rs

@@ -4144,7 +4144,7 @@ pub fn positional_element_ty<'tcx>(cx: &ctxt<'tcx>,
                                    variant: Option<ast::DefId>) -> Option<Ty<'tcx>> {
 
     match (&ty.sty, variant) {
-        (&ty_tup(ref v), None) => v.get(i).map(|&t| t),
+        (&ty_tup(ref v), None) => v.get(i).cloned(),
 
 
         (&ty_struct(def_id, substs), None) => lookup_struct_fields(cx, def_id)

src/librustc_trans/trans/closure.rs

@@ -208,7 +208,7 @@ pub fn trans_closure_expr<'a, 'tcx>(dest: Dest<'a, 'tcx>,
     let function_type = typer.closure_type(closure_id, param_substs);
 
     let freevars: Vec<ty::Freevar> =
-        ty::with_freevars(tcx, id, |fv| fv.iter().map(|&fv| fv).collect());
+        ty::with_freevars(tcx, id, |fv| fv.iter().cloned().collect());
 
     let sig = ty::erase_late_bound_regions(tcx, &function_type.sig);
 

src/librustc_typeck/check/mod.rs

@@ -640,7 +640,7 @@ fn check_fn<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
     // Remember return type so that regionck can access it later.
     let mut fn_sig_tys: Vec<Ty> =
         arg_tys.iter()
-        .map(|&ty| ty)
+        .cloned()
         .collect();
 
     if let ty::FnConverging(ret_ty) = ret_ty {

src/libstd/old_path/posix.rs

@@ -1172,7 +1172,7 @@ mod tests {
                     let exp: &[&[u8]] = &[$($exp),*];
                     assert_eq!(comps, exp);
                     let comps = path.components().rev().collect::<Vec<&[u8]>>();
-                    let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&[u8]>>();
+                    let exp = exp.iter().rev().cloned().collect::<Vec<&[u8]>>();
                     assert_eq!(comps, exp)
                 }
             )
@@ -1204,7 +1204,7 @@ mod tests {
                     let exp: &[Option<&str>] = &$exp;
                     assert_eq!(comps, exp);
                     let comps = path.str_components().rev().collect::<Vec<Option<&str>>>();
-                    let exp = exp.iter().rev().map(|&x|x).collect::<Vec<Option<&str>>>();
+                    let exp = exp.iter().rev().cloned().collect::<Vec<Option<&str>>>();
                     assert_eq!(comps, exp);
                 }
             )

src/libstd/old_path/windows.rs

@@ -2226,7 +2226,7 @@ mod tests {
                     assert_eq!(comps, exp);
                     let comps = path.str_components().rev().map(|x|x.unwrap())
                                 .collect::<Vec<&str>>();
-                    let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&str>>();
+                    let exp = exp.iter().rev().cloned().collect::<Vec<&str>>();
                     assert_eq!(comps, exp);
                 }
             );
@@ -2282,7 +2282,7 @@ mod tests {
                     let exp: &[&[u8]] = &$exp;
                     assert_eq!(comps, exp);
                     let comps = path.components().rev().collect::<Vec<&[u8]>>();
-                    let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&[u8]>>();
+                    let exp = exp.iter().rev().cloned().collect::<Vec<&[u8]>>();
                     assert_eq!(comps, exp);
                 }
             )

src/libstd/rand/mod.rs

@@ -547,7 +547,7 @@ mod test {
     #[test]
     fn test_choose() {
         let mut r = thread_rng();
-        assert_eq!(r.choose(&[1, 1, 1]).map(|&x|x), Some(1));
+        assert_eq!(r.choose(&[1, 1, 1]).cloned(), Some(1));
 
         let v: &[int] = &[];
         assert_eq!(r.choose(v), None);

src/libsyntax/diagnostics/registry.rs

@@ -17,7 +17,7 @@ pub struct Registry {
 
 impl Registry {
     pub fn new(descriptions: &[(&'static str, &'static str)]) -> Registry {
-        Registry { descriptions: descriptions.iter().map(|&tuple| tuple).collect() }
+        Registry { descriptions: descriptions.iter().cloned().collect() }
     }
 
     pub fn find_description(&self, code: &str) -> Option<&'static str> {

src/libsyntax/parse/parser.rs

@@ -1705,7 +1705,7 @@ impl<'a> Parser<'a> {
                         (true, LitBinary(parse::binary_lit(i.as_str()))),
                     token::BinaryRaw(i, _) =>
                         (true,
-                         LitBinary(Rc::new(i.as_str().as_bytes().iter().map(|&x| x).collect()))),
+                         LitBinary(Rc::new(i.as_str().as_bytes().iter().cloned().collect()))),
                 };
 
                 if suffix_illegal {

src/libterm/terminfo/parm.rs

@@ -608,7 +608,7 @@ mod test {
             Result<Vec<u8>, String>
         {
             let mut u8v: Vec<_> = fmt.bytes().collect();
-            u8v.extend(cap.as_bytes().iter().map(|&b| b));
+            u8v.extend(cap.bytes());
             expand(&u8v, params, vars)
         }
 

src/test/bench/shootout-meteor.rs

@@ -202,7 +202,7 @@ fn filter_masks(masks: &mut Vec<Vec<Vec<u64>>>) {
     for i in 0..masks.len() {
         for j in 0..(*masks)[i].len() {
             masks[i][j] =
-                (*masks)[i][j].iter().map(|&m| m)
+                (*masks)[i][j].iter().cloned()
                 .filter(|&m| !is_board_unfeasible(m, masks))
                 .collect();
         }