Auto merge of #43012 - scottmcm:delete-range-step-by, r=alexcrichton

Delete deprecated & unstable range-specific `step_by`

Using the new one is annoying while this one exists, since the inherent method hides the one on iterator.

Tracking issue: #27741
Replacement: #41439
Deprecation: #42310 for 1.19
Fixes #41477

src/liballoc/tests/vec_deque.rs

@@ -510,8 +510,7 @@ fn test_from_iter() {
     let u: Vec<_> = deq.iter().cloned().collect();
     assert_eq!(u, v);
 
-    // FIXME #27741: Remove `.skip(0)` when Range::step_by is fully removed
-    let seq = (0..).skip(0).step_by(2).take(256);
+    let seq = (0..).step_by(2).take(256);
     let deq: VecDeque<_> = seq.collect();
     for (i, &x) in deq.iter().enumerate() {
         assert_eq!(2 * i, x);

src/libcore/iter/mod.rs

@@ -314,12 +314,6 @@
            reason = "likely to be replaced by finer-grained traits",
            issue = "42168")]
 pub use self::range::Step;
-#[unstable(feature = "step_by", reason = "recent addition",
-           issue = "27741")]
-#[rustc_deprecated(since = "1.19.0",
-                   reason = "replaced by `iter::StepBy`")]
-#[allow(deprecated)]
-pub use self::range::StepBy as DeprecatedStepBy;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::sources::{Repeat, repeat};

src/libcore/iter/range.rs

@@ -244,219 +244,6 @@ fn steps_between_by_one(start: &Self, end: &Self) -> Option<usize> {
 step_impl_no_between!(u64 i64);
 step_impl_no_between!(u128 i128);
 
-/// An adapter for stepping range iterators by a custom amount.
-///
-/// The resulting iterator handles overflow by stopping. The `A`
-/// parameter is the type being iterated over, while `R` is the range
-/// type (usually one of `std::ops::{Range, RangeFrom, RangeInclusive}`.
-#[derive(Clone, Debug)]
-#[unstable(feature = "step_by", reason = "recent addition",
-           issue = "27741")]
-#[rustc_deprecated(since = "1.19.0",
-                   reason = "replaced by `iter::StepBy`")]
-#[allow(deprecated)]
-pub struct StepBy<A, R> {
-    step_by: A,
-    range: R,
-}
-
-impl<A: Step> ops::RangeFrom<A> {
-    /// Creates an iterator starting at the same point, but stepping by
-    /// the given amount at each iteration.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(step_by)]
-    /// fn main() {
-    ///     let result: Vec<_> = (0..).step_by(2).take(5).collect();
-    ///     assert_eq!(result, vec![0, 2, 4, 6, 8]);
-    /// }
-    /// ```
-    #[unstable(feature = "step_by", reason = "recent addition",
-               issue = "27741")]
-    #[rustc_deprecated(since = "1.19.0",
-                       reason = "replaced by `Iterator::step_by`")]
-    #[allow(deprecated)]
-    pub fn step_by(self, by: A) -> StepBy<A, Self> {
-        StepBy {
-            step_by: by,
-            range: self
-        }
-    }
-}
-
-impl<A: Step> ops::Range<A> {
-    /// Creates an iterator with the same range, but stepping by the
-    /// given amount at each iteration.
-    ///
-    /// The resulting iterator handles overflow by stopping.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(step_by)]
-    /// fn main() {
-    ///     let result: Vec<_> = (0..10).step_by(2).collect();
-    ///     assert_eq!(result, vec![0, 2, 4, 6, 8]);
-    /// }
-    /// ```
-    #[unstable(feature = "step_by", reason = "recent addition",
-               issue = "27741")]
-    #[rustc_deprecated(since = "1.19.0",
-                       reason = "replaced by `Iterator::step_by`")]
-    #[allow(deprecated)]
-    pub fn step_by(self, by: A) -> StepBy<A, Self> {
-        StepBy {
-            step_by: by,
-            range: self
-        }
-    }
-}
-
-impl<A: Step> ops::RangeInclusive<A> {
-    /// Creates an iterator with the same range, but stepping by the
-    /// given amount at each iteration.
-    ///
-    /// The resulting iterator handles overflow by stopping.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(step_by, inclusive_range_syntax)]
-    ///
-    /// let result: Vec<_> = (0...10).step_by(2).collect();
-    /// assert_eq!(result, vec![0, 2, 4, 6, 8, 10]);
-    /// ```
-    #[unstable(feature = "step_by", reason = "recent addition",
-               issue = "27741")]
-    #[rustc_deprecated(since = "1.19.0",
-                       reason = "replaced by `Iterator::step_by`")]
-    #[allow(deprecated)]
-    pub fn step_by(self, by: A) -> StepBy<A, Self> {
-        StepBy {
-            step_by: by,
-            range: self
-        }
-    }
-}
-
-#[unstable(feature = "step_by", reason = "recent addition",
-           issue = "27741")]
-#[allow(deprecated)]
-impl<A> Iterator for StepBy<A, ops::RangeFrom<A>> where
-    A: Clone,
-    for<'a> &'a A: Add<&'a A, Output = A>
-{
-    type Item = A;
-
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let mut n = &self.range.start + &self.step_by;
-        mem::swap(&mut n, &mut self.range.start);
-        Some(n)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        (usize::MAX, None) // Too bad we can't specify an infinite lower bound
-    }
-}
-
-#[unstable(feature = "fused", issue = "35602")]
-#[allow(deprecated)]
-impl<A> FusedIterator for StepBy<A, ops::RangeFrom<A>>
-    where A: Clone, for<'a> &'a A: Add<&'a A, Output = A> {}
-
-#[unstable(feature = "step_by", reason = "recent addition",
-           issue = "27741")]
-#[allow(deprecated)]
-impl<A: Step + Clone> Iterator for StepBy<A, ops::Range<A>> {
-    type Item = A;
-
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let rev = self.step_by.is_negative();
-        if (rev && self.range.start > self.range.end) ||
-           (!rev && self.range.start < self.range.end)
-        {
-            match self.range.start.step(&self.step_by) {
-                Some(mut n) => {
-                    mem::swap(&mut self.range.start, &mut n);
-                    Some(n)
-                },
-                None => {
-                    let mut n = self.range.end.clone();
-                    mem::swap(&mut self.range.start, &mut n);
-                    Some(n)
-                }
-            }
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        match Step::steps_between(&self.range.start,
-                                  &self.range.end,
-                                  &self.step_by) {
-            Some(hint) => (hint, Some(hint)),
-            None       => (0, None)
-        }
-    }
-}
-
-#[unstable(feature = "fused", issue = "35602")]
-#[allow(deprecated)]
-impl<A: Step + Clone> FusedIterator for StepBy<A, ops::Range<A>> {}
-
-#[unstable(feature = "inclusive_range",
-           reason = "recently added, follows RFC",
-           issue = "28237")]
-#[allow(deprecated)]
-impl<A: Step + Clone> Iterator for StepBy<A, ops::RangeInclusive<A>> {
-    type Item = A;
-
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let rev = self.step_by.is_negative();
-
-        if (rev && self.range.start >= self.range.end) ||
-           (!rev && self.range.start <= self.range.end)
-        {
-            match self.range.start.step(&self.step_by) {
-                Some(n) => {
-                    Some(mem::replace(&mut self.range.start, n))
-                },
-                None => {
-                    let last = self.range.start.replace_one();
-                    self.range.end.replace_zero();
-                    self.step_by.replace_one();
-                    Some(last)
-                },
-            }
-        }
-        else {
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        match Step::steps_between(&self.range.start,
-                                  &self.range.end,
-                                  &self.step_by) {
-            Some(hint) => (hint.saturating_add(1), hint.checked_add(1)),
-            None       => (0, None)
-        }
-    }
-}
-
-#[unstable(feature = "fused", issue = "35602")]
-#[allow(deprecated)]
-impl<A: Step + Clone> FusedIterator for StepBy<A, ops::RangeInclusive<A>> {}
-
 macro_rules! range_exact_iter_impl {
     ($($t:ty)*) => ($(
         #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/tests/iter.rs

@@ -12,15 +12,6 @@
 use core::{i8, i16, isize};
 use core::usize;
 
-// FIXME #27741: This is here to simplify calling Iterator::step_by. Remove
-// once Range::step_by is completely gone (not just deprecated).
-trait IterEx: Sized {
-    fn iter_step_by(self, n: usize) -> StepBy<Self>;
-}
-impl<I:Iterator> IterEx for I {
-    fn iter_step_by(self, n: usize) -> StepBy<Self> { self.step_by(n) }
-}
-
 #[test]
 fn test_lt() {
     let empty: [isize; 0] = [];
@@ -76,7 +67,7 @@ fn test_multi_iter() {
 
 #[test]
 fn test_counter_from_iter() {
-    let it = (0..).iter_step_by(5).take(10);
+    let it = (0..).step_by(5).take(10);
     let xs: Vec<isize> = FromIterator::from_iter(it);
     assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
 }
@@ -94,7 +85,7 @@ fn test_iterator_chain() {
     }
     assert_eq!(i, expected.len());
 
-    let ys = (30..).iter_step_by(10).take(4);
+    let ys = (30..).step_by(10).take(4);
     let it = xs.iter().cloned().chain(ys);
     let mut i = 0;
     for x in it {
@@ -156,13 +147,13 @@ fn test_iterator_chain_find() {
 #[test]
 fn test_iterator_step_by() {
     // Identity
-    let mut it = (0..).iter_step_by(1).take(3);
+    let mut it = (0..).step_by(1).take(3);
     assert_eq!(it.next(), Some(0));
     assert_eq!(it.next(), Some(1));
     assert_eq!(it.next(), Some(2));
     assert_eq!(it.next(), None);
 
-    let mut it = (0..).iter_step_by(3).take(4);
+    let mut it = (0..).step_by(3).take(4);
     assert_eq!(it.next(), Some(0));
     assert_eq!(it.next(), Some(3));
     assert_eq!(it.next(), Some(6));
@@ -173,7 +164,7 @@ fn test_iterator_step_by() {
 #[test]
 #[should_panic]
 fn test_iterator_step_by_zero() {
-    let mut it = (0..).iter_step_by(0);
+    let mut it = (0..).step_by(0);
     it.next();
 }
 
@@ -252,7 +243,7 @@ fn test(self) -> bool { true }
 
 #[test]
 fn test_filter_map() {
-    let it = (0..).iter_step_by(1).take(10)
+    let it = (0..).step_by(1).take(10)
         .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
     assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
 }
@@ -654,7 +645,7 @@ fn add(old: &mut isize, new: &usize) -> Option<f64> {
 fn test_iterator_flat_map() {
     let xs = [0, 3, 6];
     let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
-    let it = xs.iter().flat_map(|&x| (x..).iter_step_by(1).take(3));
+    let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
     let mut i = 0;
     for x in it {
         assert_eq!(x, ys[i]);
@@ -680,13 +671,13 @@ fn test_inspect() {
 #[test]
 fn test_cycle() {
     let cycle_len = 3;
-    let it = (0..).iter_step_by(1).take(cycle_len).cycle();
+    let it = (0..).step_by(1).take(cycle_len).cycle();
     assert_eq!(it.size_hint(), (usize::MAX, None));
     for (i, x) in it.take(100).enumerate() {
         assert_eq!(i % cycle_len, x);
     }
 
-    let mut it = (0..).iter_step_by(1).take(0).cycle();
+    let mut it = (0..).step_by(1).take(0).cycle();
     assert_eq!(it.size_hint(), (0, Some(0)));
     assert_eq!(it.next(), None);
 }
@@ -765,7 +756,7 @@ fn test_iterator_min() {
 
 #[test]
 fn test_iterator_size_hint() {
-    let c = (0..).iter_step_by(1);
+    let c = (0..).step_by(1);
     let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
     let v2 = &[10, 11, 12];
     let vi = v.iter();
@@ -1090,8 +1081,8 @@ fn test_range_step() {
     #![allow(deprecated)]
 
     assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
-    assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
-    assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
+    assert_eq!((1..21).rev().step_by(5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
+    assert_eq!((1..21).rev().step_by(6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
     assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
     assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
     assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
@@ -1099,13 +1090,12 @@ fn test_range_step() {
     assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
     assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
     assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
-    assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
-    assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
+    assert_eq!((1..21).rev().step_by(5).size_hint(), (4, Some(4)));
+    assert_eq!((1..21).rev().step_by(6).size_hint(), (4, Some(4)));
     assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
     assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
-    assert_eq!((0..1).step_by(0).size_hint(), (0, None));
-    assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
-    assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
+    assert_eq!((i8::MIN..i8::MAX).step_by(-(i8::MIN as i32) as usize).size_hint(), (2, Some(2)));
+    assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX as usize).size_hint(), (3, Some(3)));
     assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
 }
 

src/libcore/tests/lib.rs

@@ -35,7 +35,6 @@
 #![feature(slice_rotate)]
 #![feature(sort_internals)]
 #![feature(specialization)]
-#![feature(step_by)]
 #![feature(step_trait)]
 #![feature(test)]
 #![feature(trusted_len)]

src/librand/lib.rs

@@ -31,7 +31,7 @@
             issue = "27703")]
 #![feature(core_intrinsics)]
 #![feature(staged_api)]
-#![feature(step_by)]
+#![feature(iterator_step_by)]
 #![feature(custom_attribute)]
 #![feature(specialization)]
 #![allow(unused_attributes)]

src/test/run-pass/range_inclusive.rs

@@ -10,7 +10,7 @@
 
 // Test inclusive range syntax.
 
-#![feature(inclusive_range_syntax, inclusive_range, step_by)]
+#![feature(inclusive_range_syntax, inclusive_range, iterator_step_by)]
 
 use std::ops::{RangeInclusive, RangeToInclusive};
 

src/test/run-pass/sync-send-iterators-in-libcore.rs

@@ -14,7 +14,7 @@
 #![feature(iter_empty)]
 #![feature(iter_once)]
 #![feature(iter_unfold)]
-#![feature(step_by)]
+#![feature(iterator_step_by)]
 #![feature(str_escape)]
 
 use std::iter::{empty, once, repeat};