Merge #624

624: Hellow554 lints 1 r=phimuemue a=phimuemue

First batch of #618.

bors r+

Co-authored-by: Marcel Hellwig <github@cookiesoft.de>

src/concat_impl.rs

@@ -18,5 +18,5 @@ pub fn concat<I>(iterable: I) -> I::Item
     where I: IntoIterator,
           I::Item: Extend<<<I as IntoIterator>::Item as IntoIterator>::Item> + IntoIterator + Default
 {
-    iterable.into_iter().fold1(|mut a, b| { a.extend(b); a }).unwrap_or_else(<_>::default)
+    iterable.into_iter().fold1(|mut a, b| { a.extend(b); a }).unwrap_or_default()
 }

src/groupbylazy.rs

@@ -7,7 +7,7 @@ trait KeyFunction<A> {
     fn call_mut(&mut self, arg: A) -> Self::Key;
 }
 
-impl<'a, A, K, F: ?Sized> KeyFunction<A> for F
+impl<A, K, F: ?Sized> KeyFunction<A> for F
     where F: FnMut(A) -> K
 {
     type Key = K;
@@ -37,7 +37,7 @@ impl ChunkIndex {
     }
 }
 
-impl<'a, A> KeyFunction<A> for ChunkIndex {
+impl<A> KeyFunction<A> for ChunkIndex {
     type Key = usize;
     #[inline(always)]
     fn call_mut(&mut self, _arg: A) -> Self::Key {

src/grouping_map.rs

@@ -289,7 +289,7 @@ impl<I, K, V> GroupingMap<I>
         where F: FnMut(&K, &V) -> CK,
               CK: Ord,
     {
-        self.max_by(|key, v1, v2| f(key, &v1).cmp(&f(key, &v2)))
+        self.max_by(|key, v1, v2| f(key, v1).cmp(&f(key, v2)))
     }
 
     /// Groups elements from the `GroupingMap` source by key and finds the minimum of each group.
@@ -367,7 +367,7 @@ impl<I, K, V> GroupingMap<I>
         where F: FnMut(&K, &V) -> CK,
               CK: Ord,
     {
-        self.min_by(|key, v1, v2| f(key, &v1).cmp(&f(key, &v2)))
+        self.min_by(|key, v1, v2| f(key, v1).cmp(&f(key, v2)))
     }
 
     /// Groups elements from the `GroupingMap` source by key and find the maximum and minimum of
@@ -480,7 +480,7 @@ impl<I, K, V> GroupingMap<I>
         where F: FnMut(&K, &V) -> CK,
               CK: Ord,
     {
-        self.minmax_by(|key, v1, v2| f(key, &v1).cmp(&f(key, &v2)))
+        self.minmax_by(|key, v1, v2| f(key, v1).cmp(&f(key, v2)))
     }
 
     /// Groups elements from the `GroupingMap` source by key and sums them.

src/intersperse.rs

@@ -107,8 +107,7 @@ impl<I, ElemF> Iterator for IntersperseWith<I, ElemF>
         self.iter.fold(accum,
             |accum, x| {
                 let accum = f(accum, element.generate());
-                let accum = f(accum, x);
-                accum
+                f(accum, x)
         })
     }
 }

src/lib.rs

@@ -1797,7 +1797,7 @@ pub trait Itertools : Iterator {
         Some(if predicate(&first) {
             first
         } else {
-            self.find(|x| predicate(&x)).unwrap_or(first)
+            self.find(|x| predicate(x)).unwrap_or(first)
         })
     }
     /// Returns `true` if the given item is present in this iterator.
@@ -2694,7 +2694,6 @@ pub trait Itertools : Iterator {
     /// itertools::assert_equal(oldest_people_first,
     ///                         vec!["Jill", "Jack", "Jane", "John"]);
     /// ```
-    /// ```
     #[cfg(feature = "use_alloc")]
     fn sorted_by_cached_key<K, F>(self, f: F) -> VecIntoIter<Self::Item>
     where

src/multipeek_impl.rs

@@ -71,10 +71,8 @@ impl<I> PeekingNext for MultiPeek<I>
             if let Some(r) = self.peek() {
                 if !accept(r) { return None }
             }
-        } else {
-            if let Some(r) = self.buf.get(0) {
-                if !accept(r) { return None }
-            }
+        } else if let Some(r) = self.buf.get(0) {
+            if !accept(r) { return None }
         }
         self.next()
     }

src/ziptuple.rs

@@ -36,6 +36,7 @@ pub struct Zip<T> {
 ///
 /// assert_eq!(results, [0 + 3, 10 + 7, 29, 36]);
 /// ```
+/// [`izip!()`]: crate::izip
 pub fn multizip<T, U>(t: U) -> Zip<T>
     where Zip<T>: From<U>,
           Zip<T>: Iterator,

tests/quick.rs

@@ -258,12 +258,12 @@ where
         let mut it = get_it();
 
         for _ in 0..(counts.len() - 1) {
-            if let None = it.next() {
+            if it.next().is_none() {
                 panic!("Iterator shouldn't be finished, may not be deterministic");
             }
         }
 
-        if let None = it.next() {
+        if it.next().is_none() {
             break 'outer;
         }
 
@@ -721,7 +721,7 @@ quickcheck! {
 
         assert_eq!(expected_first, curr_perm);
 
-        while let Some(next_perm) = perms.next() {
+        for next_perm in perms {
             assert!(
                 next_perm > curr_perm,
                 "next perm isn't greater-than current; next_perm={:?} curr_perm={:?} n={}",
@@ -943,8 +943,7 @@ quickcheck! {
     fn fuzz_group_by_lazy_1(it: Iter<u8>) -> bool {
         let jt = it.clone();
         let groups = it.group_by(|k| *k);
-        let res = itertools::equal(jt, groups.into_iter().flat_map(|(_, x)| x));
-        res
+        itertools::equal(jt, groups.into_iter().flat_map(|(_, x)| x))
     }
 }
 
@@ -1286,7 +1285,7 @@ quickcheck! {
             .map(|i| (i % modulo, i))
             .into_group_map()
             .into_iter()
-            .map(|(key, vals)| (key, vals.into_iter().fold(0u64, |acc, val| acc + val)))
+            .map(|(key, vals)| (key, vals.into_iter().sum()))
             .collect::<HashMap<_,_>>();
         assert_eq!(lookup, group_map_lookup);
 
@@ -1551,7 +1550,6 @@ quickcheck! {
 }
 
 quickcheck! {
-    #[test]
     fn counts(nums: Vec<isize>) -> TestResult {
         let counts = nums.iter().counts();
         for (&item, &count) in counts.iter() {
@@ -1602,7 +1600,7 @@ quickcheck! {
 
 fn is_fused<I: Iterator>(mut it: I) -> bool
 {
-    while let Some(_) = it.next() {}
+    for _ in it.by_ref() {}
     for _ in 0..10{
         if it.next().is_some(){
             return false;

tests/specializations.rs

@@ -129,7 +129,7 @@ quickcheck! {
             check_results_specialized!(it, |i| {
                 let mut parameters_from_fold = vec![];
                 let fold_result = i.fold(vec![], |mut acc, v| {
-                    parameters_from_fold.push((acc.clone(), v.clone()));
+                    parameters_from_fold.push((acc.clone(), v));
                     acc.push(v);
                     acc
                 });
@@ -139,7 +139,7 @@ quickcheck! {
                 let mut parameters_from_all = vec![];
                 let first = i.next();
                 let all_result = i.all(|x| {
-                    parameters_from_all.push(x.clone());
+                    parameters_from_all.push(x);
                     Some(x)==first
                 });
                 (parameters_from_all, all_result)

tests/test_core.rs

@@ -116,7 +116,7 @@ fn chain2() {
 fn write_to() {
     let xs = [7, 9, 8];
     let mut ys = [0; 5];
-    let cnt = ys.iter_mut().set_from(xs.iter().map(|x| *x));
+    let cnt = ys.iter_mut().set_from(xs.iter().copied());
     assert!(cnt == xs.len());
     assert!(ys == [7, 9, 8, 0, 0]);
 

tests/test_std.rs

@@ -123,12 +123,12 @@ fn unique() {
 #[test]
 fn intersperse() {
     let xs = ["a", "", "b", "c"];
-    let v: Vec<&str> = xs.iter().map(|x| x.clone()).intersperse(", ").collect();
+    let v: Vec<&str> = xs.iter().cloned().intersperse(", ").collect();
     let text: String = v.concat();
     assert_eq!(text, "a, , b, c".to_string());
 
     let ys = [0, 1, 2, 3];
-    let mut it = ys[..0].iter().map(|x| *x).intersperse(1);
+    let mut it = ys[..0].iter().copied().intersperse(1);
     assert!(it.next() == None);
 }
 
@@ -474,7 +474,7 @@ impl<T: Clone + Send, R: Clone + Rng + SeedableRng + Send> qc::Arbitrary for Ran
 
 // Check that taking the k smallest is the same as
 //  sorting then taking the k first elements
-fn k_smallest_sort<I>(i: I, k: u16) -> ()
+fn k_smallest_sort<I>(i: I, k: u16)
 where
     I: Iterator + Clone,
     I::Item: Ord + Debug,
@@ -538,10 +538,10 @@ fn sorted_by_cached_key() {
 fn test_multipeek() {
     let nums = vec![1u8,2,3,4,5];
 
-    let mp = multipeek(nums.iter().map(|&x| x));
+    let mp = multipeek(nums.iter().copied());
     assert_eq!(nums, mp.collect::<Vec<_>>());
 
-    let mut mp = multipeek(nums.iter().map(|&x| x));
+    let mut mp = multipeek(nums.iter().copied());
     assert_eq!(mp.peek(), Some(&1));
     assert_eq!(mp.next(), Some(1));
     assert_eq!(mp.peek(), Some(&2));
@@ -579,7 +579,7 @@ fn test_multipeek_peeking_next() {
     use crate::it::PeekingNext;
     let nums = vec![1u8,2,3,4,5,6,7];
 
-    let mut mp = multipeek(nums.iter().map(|&x| x));
+    let mut mp = multipeek(nums.iter().copied());
     assert_eq!(mp.peeking_next(|&x| x != 0), Some(1));
     assert_eq!(mp.next(), Some(2));
     assert_eq!(mp.peek(), Some(&3));
@@ -604,10 +604,10 @@ fn test_multipeek_peeking_next() {
 fn test_peek_nth() {
     let nums = vec![1u8,2,3,4,5];
 
-    let iter = peek_nth(nums.iter().map(|&x| x));
+    let iter = peek_nth(nums.iter().copied());
     assert_eq!(nums, iter.collect::<Vec<_>>());
 
-    let mut iter = peek_nth(nums.iter().map(|&x| x));
+    let mut iter = peek_nth(nums.iter().copied());
 
     assert_eq!(iter.peek_nth(0), Some(&1));
     assert_eq!(iter.peek_nth(0), Some(&1));
@@ -638,7 +638,7 @@ fn test_peek_nth() {
 fn test_peek_nth_peeking_next() {
     use it::PeekingNext;
     let nums = vec![1u8,2,3,4,5,6,7];
-    let mut iter = peek_nth(nums.iter().map(|&x| x));
+    let mut iter = peek_nth(nums.iter().copied());
 
     assert_eq!(iter.peeking_next(|&x| x != 0), Some(1));
     assert_eq!(iter.next(), Some(2));
@@ -694,7 +694,7 @@ fn group_by() {
         }
     }
 
-    let toupper = |ch: &char| ch.to_uppercase().nth(0).unwrap();
+    let toupper = |ch: &char| ch.to_uppercase().next().unwrap();
 
     // try all possible orderings
     for indices in permutohedron::Heap::new(&mut [0, 1, 2, 3]) {
@@ -1091,9 +1091,9 @@ fn format() {
     let t2 = format!("{:?}", data.iter().format("--"));
     assert_eq!(t2, ans2);
 
-    let dataf = [1.1, 2.71828, -22.];
+    let dataf = [1.1, 5.71828, -22.];
     let t3 = format!("{:.2e}", dataf.iter().format(", "));
-    assert_eq!(t3, "1.10e0, 2.72e0, -2.20e1");
+    assert_eq!(t3, "1.10e0, 5.72e0, -2.20e1");
 }
 
 #[test]
@@ -1110,7 +1110,7 @@ fn fold_while() {
     let vec = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
     let sum = vec.into_iter().fold_while(0, |acc, item| {
         iterations += 1;
-        let new_sum = acc.clone() + item;
+        let new_sum = acc + item;
         if new_sum <= 20 {
             FoldWhile::Continue(new_sum)
         } else {
@@ -1143,7 +1143,7 @@ fn tree_fold1() {
         "0 1 x 2 3 x x 4 5 x 6 7 x x x 8 9 x 10 11 x x 12 13 x 14 15 x x x x",
     ];
     for (i, &s) in x.iter().enumerate() {
-        let expected = if s == "" { None } else { Some(s.to_string()) };
+        let expected = if s.is_empty() { None } else { Some(s.to_string()) };
         let num_strings = (0..i).map(|x| x.to_string());
         let actual = num_strings.tree_fold1(|a, b| format!("{} {} x", a, b));
         assert_eq!(actual, expected);

tests/zip.rs

@@ -29,8 +29,8 @@ fn test_zip_longest_size_hint() {
 fn test_double_ended_zip_longest() {
     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().copied();
+    let b = ys.iter().copied();
     let mut it = a.zip_longest(b);
     assert_eq!(it.next(), Some(Both(1, 1)));
     assert_eq!(it.next(), Some(Both(2, 2)));
@@ -45,8 +45,8 @@ fn test_double_ended_zip_longest() {
 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().copied();
+    let b = ys.iter().copied();
     let mut it = multizip((a, b));
     assert_eq!(it.next_back(), Some((4, 7)));
     assert_eq!(it.next_back(), Some((3, 3)));