library/alloc/tests/slice.rs

   1 use std::cell::Cell;
   2 use std::cmp::Ordering::{self, Equal, Greater, Less};
   3 use std::convert::identity;
   4 use std::mem;
   5 use std::panic;
   6 use std::rc::Rc;
   7 use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
   8
   9 use rand::distributions::Standard;
  10 use rand::seq::SliceRandom;
  11 use rand::{thread_rng, Rng, RngCore};
  12
  13 fn square(n: usize) -> usize {
  14     n * n
  15 }
  16
  17 fn is_odd(n: &usize) -> bool {
  18     *n % 2 == 1
  19 }
  20
  21 #[test]
  22 fn test_from_fn() {
  23     // Test on-stack from_fn.
  24     let mut v: Vec<_> = (0..3).map(square).collect();
  25     {
  26         let v = v;
  27         assert_eq!(v.len(), 3);
  28         assert_eq!(v[0], 0);
  29         assert_eq!(v[1], 1);
  30         assert_eq!(v[2], 4);
  31     }
  32
  33     // Test on-heap from_fn.
  34     v = (0..5).map(square).collect();
  35     {
  36         let v = v;
  37         assert_eq!(v.len(), 5);
  38         assert_eq!(v[0], 0);
  39         assert_eq!(v[1], 1);
  40         assert_eq!(v[2], 4);
  41         assert_eq!(v[3], 9);
  42         assert_eq!(v[4], 16);
  43     }
  44 }
  45
  46 #[test]
  47 fn test_from_elem() {
  48     // Test on-stack from_elem.
  49     let mut v = vec![10, 10];
  50     {
  51         let v = v;
  52         assert_eq!(v.len(), 2);
  53         assert_eq!(v[0], 10);
  54         assert_eq!(v[1], 10);
  55     }
  56
  57     // Test on-heap from_elem.
  58     v = vec![20; 6];
  59     {
  60         let v = &v[..];
  61         assert_eq!(v[0], 20);
  62         assert_eq!(v[1], 20);
  63         assert_eq!(v[2], 20);
  64         assert_eq!(v[3], 20);
  65         assert_eq!(v[4], 20);
  66         assert_eq!(v[5], 20);
  67     }
  68 }
  69
  70 #[test]
  71 fn test_is_empty() {
  72     let xs: [i32; 0] = [];
  73     assert!(xs.is_empty());
  74     assert!(![0].is_empty());
  75 }
  76
  77 #[test]
  78 fn test_len_divzero() {
  79     type Z = [i8; 0];
  80     let v0: &[Z] = &[];
  81     let v1: &[Z] = &[[]];
  82     let v2: &[Z] = &[[], []];
  83     assert_eq!(mem::size_of::<Z>(), 0);
  84     assert_eq!(v0.len(), 0);
  85     assert_eq!(v1.len(), 1);
  86     assert_eq!(v2.len(), 2);
  87 }
  88
  89 #[test]
  90 fn test_get() {
  91     let mut a = vec![11];
  92     assert_eq!(a.get(1), None);
  93     a = vec![11, 12];
  94     assert_eq!(a.get(1).unwrap(), &12);
  95     a = vec![11, 12, 13];
  96     assert_eq!(a.get(1).unwrap(), &12);
  97 }
  98
  99 #[test]
 100 fn test_first() {
 101     let mut a = vec![];
 102     assert_eq!(a.first(), None);
 103     a = vec![11];
 104     assert_eq!(a.first().unwrap(), &11);
 105     a = vec![11, 12];
 106     assert_eq!(a.first().unwrap(), &11);
 107 }
 108
 109 #[test]
 110 fn test_first_mut() {
 111     let mut a = vec![];
 112     assert_eq!(a.first_mut(), None);
 113     a = vec![11];
 114     assert_eq!(*a.first_mut().unwrap(), 11);
 115     a = vec![11, 12];
 116     assert_eq!(*a.first_mut().unwrap(), 11);
 117 }
 118
 119 #[test]
 120 fn test_split_first() {
 121     let mut a = vec![11];
 122     let b: &[i32] = &[];
 123     assert!(b.split_first().is_none());
 124     assert_eq!(a.split_first(), Some((&11, b)));
 125     a = vec![11, 12];
 126     let b: &[i32] = &[12];
 127     assert_eq!(a.split_first(), Some((&11, b)));
 128 }
 129
 130 #[test]
 131 fn test_split_first_mut() {
 132     let mut a = vec![11];
 133     let b: &mut [i32] = &mut [];
 134     assert!(b.split_first_mut().is_none());
 135     assert!(a.split_first_mut() == Some((&mut 11, b)));
 136     a = vec![11, 12];
 137     let b: &mut [_] = &mut [12];
 138     assert!(a.split_first_mut() == Some((&mut 11, b)));
 139 }
 140
 141 #[test]
 142 fn test_split_last() {
 143     let mut a = vec![11];
 144     let b: &[i32] = &[];
 145     assert!(b.split_last().is_none());
 146     assert_eq!(a.split_last(), Some((&11, b)));
 147     a = vec![11, 12];
 148     let b: &[_] = &[11];
 149     assert_eq!(a.split_last(), Some((&12, b)));
 150 }
 151
 152 #[test]
 153 fn test_split_last_mut() {
 154     let mut a = vec![11];
 155     let b: &mut [i32] = &mut [];
 156     assert!(b.split_last_mut().is_none());
 157     assert!(a.split_last_mut() == Some((&mut 11, b)));
 158
 159     a = vec![11, 12];
 160     let b: &mut [_] = &mut [11];
 161     assert!(a.split_last_mut() == Some((&mut 12, b)));
 162 }
 163
 164 #[test]
 165 fn test_last() {
 166     let mut a = vec![];
 167     assert_eq!(a.last(), None);
 168     a = vec![11];
 169     assert_eq!(a.last().unwrap(), &11);
 170     a = vec![11, 12];
 171     assert_eq!(a.last().unwrap(), &12);
 172 }
 173
 174 #[test]
 175 fn test_last_mut() {
 176     let mut a = vec![];
 177     assert_eq!(a.last_mut(), None);
 178     a = vec![11];
 179     assert_eq!(*a.last_mut().unwrap(), 11);
 180     a = vec![11, 12];
 181     assert_eq!(*a.last_mut().unwrap(), 12);
 182 }
 183
 184 #[test]
 185 fn test_slice() {
 186     // Test fixed length vector.
 187     let vec_fixed = [1, 2, 3, 4];
 188     let v_a = vec_fixed[1..vec_fixed.len()].to_vec();
 189     assert_eq!(v_a.len(), 3);
 190
 191     assert_eq!(v_a[0], 2);
 192     assert_eq!(v_a[1], 3);
 193     assert_eq!(v_a[2], 4);
 194
 195     // Test on stack.
 196     let vec_stack: &[_] = &[1, 2, 3];
 197     let v_b = vec_stack[1..3].to_vec();
 198     assert_eq!(v_b.len(), 2);
 199
 200     assert_eq!(v_b[0], 2);
 201     assert_eq!(v_b[1], 3);
 202
 203     // Test `Box<[T]>`
 204     let vec_unique = vec![1, 2, 3, 4, 5, 6];
 205     let v_d = vec_unique[1..6].to_vec();
 206     assert_eq!(v_d.len(), 5);
 207
 208     assert_eq!(v_d[0], 2);
 209     assert_eq!(v_d[1], 3);
 210     assert_eq!(v_d[2], 4);
 211     assert_eq!(v_d[3], 5);
 212     assert_eq!(v_d[4], 6);
 213 }
 214
 215 #[test]
 216 fn test_slice_from() {
 217     let vec: &[_] = &[1, 2, 3, 4];
 218     assert_eq!(&vec[..], vec);
 219     let b: &[_] = &[3, 4];
 220     assert_eq!(&vec[2..], b);
 221     let b: &[_] = &[];
 222     assert_eq!(&vec[4..], b);
 223 }
 224
 225 #[test]
 226 fn test_slice_to() {
 227     let vec: &[_] = &[1, 2, 3, 4];
 228     assert_eq!(&vec[..4], vec);
 229     let b: &[_] = &[1, 2];
 230     assert_eq!(&vec[..2], b);
 231     let b: &[_] = &[];
 232     assert_eq!(&vec[..0], b);
 233 }
 234
 235 #[test]
 236 fn test_pop() {
 237     let mut v = vec![5];
 238     let e = v.pop();
 239     assert_eq!(v.len(), 0);
 240     assert_eq!(e, Some(5));
 241     let f = v.pop();
 242     assert_eq!(f, None);
 243     let g = v.pop();
 244     assert_eq!(g, None);
 245 }
 246
 247 #[test]
 248 fn test_swap_remove() {
 249     let mut v = vec![1, 2, 3, 4, 5];
 250     let mut e = v.swap_remove(0);
 251     assert_eq!(e, 1);
 252     assert_eq!(v, [5, 2, 3, 4]);
 253     e = v.swap_remove(3);
 254     assert_eq!(e, 4);
 255     assert_eq!(v, [5, 2, 3]);
 256 }
 257
 258 #[test]
 259 #[should_panic]
 260 fn test_swap_remove_fail() {
 261     let mut v = vec![1];
 262     let _ = v.swap_remove(0);
 263     let _ = v.swap_remove(0);
 264 }
 265
 266 #[test]
 267 fn test_swap_remove_noncopyable() {
 268     // Tests that we don't accidentally run destructors twice.
 269     let mut v: Vec<Box<_>> = Vec::new();
 270     v.push(box 0);
 271     v.push(box 0);
 272     v.push(box 0);
 273     let mut _e = v.swap_remove(0);
 274     assert_eq!(v.len(), 2);
 275     _e = v.swap_remove(1);
 276     assert_eq!(v.len(), 1);
 277     _e = v.swap_remove(0);
 278     assert_eq!(v.len(), 0);
 279 }
 280
 281 #[test]
 282 fn test_push() {
 283     // Test on-stack push().
 284     let mut v = vec![];
 285     v.push(1);
 286     assert_eq!(v.len(), 1);
 287     assert_eq!(v[0], 1);
 288
 289     // Test on-heap push().
 290     v.push(2);
 291     assert_eq!(v.len(), 2);
 292     assert_eq!(v[0], 1);
 293     assert_eq!(v[1], 2);
 294 }
 295
 296 #[test]
 297 fn test_truncate() {
 298     let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
 299     v.truncate(1);
 300     let v = v;
 301     assert_eq!(v.len(), 1);
 302     assert_eq!(*(v[0]), 6);
 303     // If the unsafe block didn't drop things properly, we blow up here.
 304 }
 305
 306 #[test]
 307 fn test_clear() {
 308     let mut v: Vec<Box<_>> = vec![box 6, box 5, box 4];
 309     v.clear();
 310     assert_eq!(v.len(), 0);
 311     // If the unsafe block didn't drop things properly, we blow up here.
 312 }
 313
 314 #[test]
 315 fn test_retain() {
 316     let mut v = vec![1, 2, 3, 4, 5];
 317     v.retain(is_odd);
 318     assert_eq!(v, [1, 3, 5]);
 319 }
 320
 321 #[test]
 322 fn test_binary_search() {
 323     assert_eq!([1, 2, 3, 4, 5].binary_search(&5).ok(), Some(4));
 324     assert_eq!([1, 2, 3, 4, 5].binary_search(&4).ok(), Some(3));
 325     assert_eq!([1, 2, 3, 4, 5].binary_search(&3).ok(), Some(2));
 326     assert_eq!([1, 2, 3, 4, 5].binary_search(&2).ok(), Some(1));
 327     assert_eq!([1, 2, 3, 4, 5].binary_search(&1).ok(), Some(0));
 328
 329     assert_eq!([2, 4, 6, 8, 10].binary_search(&1).ok(), None);
 330     assert_eq!([2, 4, 6, 8, 10].binary_search(&5).ok(), None);
 331     assert_eq!([2, 4, 6, 8, 10].binary_search(&4).ok(), Some(1));
 332     assert_eq!([2, 4, 6, 8, 10].binary_search(&10).ok(), Some(4));
 333
 334     assert_eq!([2, 4, 6, 8].binary_search(&1).ok(), None);
 335     assert_eq!([2, 4, 6, 8].binary_search(&5).ok(), None);
 336     assert_eq!([2, 4, 6, 8].binary_search(&4).ok(), Some(1));
 337     assert_eq!([2, 4, 6, 8].binary_search(&8).ok(), Some(3));
 338
 339     assert_eq!([2, 4, 6].binary_search(&1).ok(), None);
 340     assert_eq!([2, 4, 6].binary_search(&5).ok(), None);
 341     assert_eq!([2, 4, 6].binary_search(&4).ok(), Some(1));
 342     assert_eq!([2, 4, 6].binary_search(&6).ok(), Some(2));
 343
 344     assert_eq!([2, 4].binary_search(&1).ok(), None);
 345     assert_eq!([2, 4].binary_search(&5).ok(), None);
 346     assert_eq!([2, 4].binary_search(&2).ok(), Some(0));
 347     assert_eq!([2, 4].binary_search(&4).ok(), Some(1));
 348
 349     assert_eq!([2].binary_search(&1).ok(), None);
 350     assert_eq!([2].binary_search(&5).ok(), None);
 351     assert_eq!([2].binary_search(&2).ok(), Some(0));
 352
 353     assert_eq!([].binary_search(&1).ok(), None);
 354     assert_eq!([].binary_search(&5).ok(), None);
 355
 356     assert!([1, 1, 1, 1, 1].binary_search(&1).ok() != None);
 357     assert!([1, 1, 1, 1, 2].binary_search(&1).ok() != None);
 358     assert!([1, 1, 1, 2, 2].binary_search(&1).ok() != None);
 359     assert!([1, 1, 2, 2, 2].binary_search(&1).ok() != None);
 360     assert_eq!([1, 2, 2, 2, 2].binary_search(&1).ok(), Some(0));
 361
 362     assert_eq!([1, 2, 3, 4, 5].binary_search(&6).ok(), None);
 363     assert_eq!([1, 2, 3, 4, 5].binary_search(&0).ok(), None);
 364 }
 365
 366 #[test]
 367 fn test_reverse() {
 368     let mut v = vec![10, 20];
 369     assert_eq!(v[0], 10);
 370     assert_eq!(v[1], 20);
 371     v.reverse();
 372     assert_eq!(v[0], 20);
 373     assert_eq!(v[1], 10);
 374
 375     let mut v3 = Vec::<i32>::new();
 376     v3.reverse();
 377     assert!(v3.is_empty());
 378
 379     // check the 1-byte-types path
 380     let mut v = (-50..51i8).collect::<Vec<_>>();
 381     v.reverse();
 382     assert_eq!(v, (-50..51i8).rev().collect::<Vec<_>>());
 383
 384     // check the 2-byte-types path
 385     let mut v = (-50..51i16).collect::<Vec<_>>();
 386     v.reverse();
 387     assert_eq!(v, (-50..51i16).rev().collect::<Vec<_>>());
 388 }
 389
 390 #[test]
 391 #[cfg_attr(miri, ignore)] // Miri is too slow
 392 fn test_sort() {
 393     let mut rng = thread_rng();
 394
 395     for len in (2..25).chain(500..510) {
 396         for &modulus in &[5, 10, 100, 1000] {
 397             for _ in 0..10 {
 398                 let orig: Vec<_> =
 399                     rng.sample_iter::<i32, _>(&Standard).map(|x| x % modulus).take(len).collect();
 400
 401                 // Sort in default order.
 402                 let mut v = orig.clone();
 403                 v.sort();
 404                 assert!(v.windows(2).all(|w| w[0] <= w[1]));
 405
 406                 // Sort in ascending order.
 407                 let mut v = orig.clone();
 408                 v.sort_by(|a, b| a.cmp(b));
 409                 assert!(v.windows(2).all(|w| w[0] <= w[1]));
 410
 411                 // Sort in descending order.
 412                 let mut v = orig.clone();
 413                 v.sort_by(|a, b| b.cmp(a));
 414                 assert!(v.windows(2).all(|w| w[0] >= w[1]));
 415
 416                 // Sort in lexicographic order.
 417                 let mut v1 = orig.clone();
 418                 let mut v2 = orig.clone();
 419                 v1.sort_by_key(|x| x.to_string());
 420                 v2.sort_by_cached_key(|x| x.to_string());
 421                 assert!(v1.windows(2).all(|w| w[0].to_string() <= w[1].to_string()));
 422                 assert!(v1 == v2);
 423
 424                 // Sort with many pre-sorted runs.
 425                 let mut v = orig.clone();
 426                 v.sort();
 427                 v.reverse();
 428                 for _ in 0..5 {
 429                     let a = rng.gen::<usize>() % len;
 430                     let b = rng.gen::<usize>() % len;
 431                     if a < b {
 432                         v[a..b].reverse();
 433                     } else {
 434                         v.swap(a, b);
 435                     }
 436                 }
 437                 v.sort();
 438                 assert!(v.windows(2).all(|w| w[0] <= w[1]));
 439             }
 440         }
 441     }
 442
 443     // Sort using a completely random comparison function.
 444     // This will reorder the elements *somehow*, but won't panic.
 445     let mut v = [0; 500];
 446     for i in 0..v.len() {
 447         v[i] = i as i32;
 448     }
 449     v.sort_by(|_, _| *[Less, Equal, Greater].choose(&mut rng).unwrap());
 450     v.sort();
 451     for i in 0..v.len() {
 452         assert_eq!(v[i], i as i32);
 453     }
 454
 455     // Should not panic.
 456     [0i32; 0].sort();
 457     [(); 10].sort();
 458     [(); 100].sort();
 459
 460     let mut v = [0xDEADBEEFu64];
 461     v.sort();
 462     assert!(v == [0xDEADBEEF]);
 463 }
 464
 465 #[test]
 466 fn test_sort_stability() {
 467     // Miri is too slow
 468     let large_range = if cfg!(miri) { 0..0 } else { 500..510 };
 469     let rounds = if cfg!(miri) { 1 } else { 10 };
 470
 471     for len in (2..25).chain(large_range) {
 472         for _ in 0..rounds {
 473             let mut counts = [0; 10];
 474
 475             // create a vector like [(6, 1), (5, 1), (6, 2), ...],
 476             // where the first item of each tuple is random, but
 477             // the second item represents which occurrence of that
 478             // number this element is, i.e., the second elements
 479             // will occur in sorted order.
 480             let orig: Vec<_> = (0..len)
 481                 .map(|_| {
 482                     let n = thread_rng().gen::<usize>() % 10;
 483                     counts[n] += 1;
 484                     (n, counts[n])
 485                 })
 486                 .collect();
 487
 488             let mut v = orig.clone();
 489             // Only sort on the first element, so an unstable sort
 490             // may mix up the counts.
 491             v.sort_by(|&(a, _), &(b, _)| a.cmp(&b));
 492
 493             // This comparison includes the count (the second item
 494             // of the tuple), so elements with equal first items
 495             // will need to be ordered with increasing
 496             // counts... i.e., exactly asserting that this sort is
 497             // stable.
 498             assert!(v.windows(2).all(|w| w[0] <= w[1]));
 499
 500             let mut v = orig.clone();
 501             v.sort_by_cached_key(|&(x, _)| x);
 502             assert!(v.windows(2).all(|w| w[0] <= w[1]));
 503         }
 504     }
 505 }
 506
 507 #[test]
 508 fn test_rotate_left() {
 509     let expected: Vec<_> = (0..13).collect();
 510     let mut v = Vec::new();
 511
 512     // no-ops
 513     v.clone_from(&expected);
 514     v.rotate_left(0);
 515     assert_eq!(v, expected);
 516     v.rotate_left(expected.len());
 517     assert_eq!(v, expected);
 518     let mut zst_array = [(), (), ()];
 519     zst_array.rotate_left(2);
 520
 521     // happy path
 522     v = (5..13).chain(0..5).collect();
 523     v.rotate_left(8);
 524     assert_eq!(v, expected);
 525
 526     let expected: Vec<_> = (0..1000).collect();
 527
 528     // small rotations in large slice, uses ptr::copy
 529     v = (2..1000).chain(0..2).collect();
 530     v.rotate_left(998);
 531     assert_eq!(v, expected);
 532     v = (998..1000).chain(0..998).collect();
 533     v.rotate_left(2);
 534     assert_eq!(v, expected);
 535
 536     // non-small prime rotation, has a few rounds of swapping
 537     v = (389..1000).chain(0..389).collect();
 538     v.rotate_left(1000 - 389);
 539     assert_eq!(v, expected);
 540 }
 541
 542 #[test]
 543 fn test_rotate_right() {
 544     let expected: Vec<_> = (0..13).collect();
 545     let mut v = Vec::new();
 546
 547     // no-ops
 548     v.clone_from(&expected);
 549     v.rotate_right(0);
 550     assert_eq!(v, expected);
 551     v.rotate_right(expected.len());
 552     assert_eq!(v, expected);
 553     let mut zst_array = [(), (), ()];
 554     zst_array.rotate_right(2);
 555
 556     // happy path
 557     v = (5..13).chain(0..5).collect();
 558     v.rotate_right(5);
 559     assert_eq!(v, expected);
 560
 561     let expected: Vec<_> = (0..1000).collect();
 562
 563     // small rotations in large slice, uses ptr::copy
 564     v = (2..1000).chain(0..2).collect();
 565     v.rotate_right(2);
 566     assert_eq!(v, expected);
 567     v = (998..1000).chain(0..998).collect();
 568     v.rotate_right(998);
 569     assert_eq!(v, expected);
 570
 571     // non-small prime rotation, has a few rounds of swapping
 572     v = (389..1000).chain(0..389).collect();
 573     v.rotate_right(389);
 574     assert_eq!(v, expected);
 575 }
 576
 577 #[test]
 578 fn test_concat() {
 579     let v: [Vec<i32>; 0] = [];
 580     let c = v.concat();
 581     assert_eq!(c, []);
 582     let d = [vec![1], vec![2, 3]].concat();
 583     assert_eq!(d, [1, 2, 3]);
 584
 585     let v: &[&[_]] = &[&[1], &[2, 3]];
 586     assert_eq!(v.join(&0), [1, 0, 2, 3]);
 587     let v: &[&[_]] = &[&[1], &[2], &[3]];
 588     assert_eq!(v.join(&0), [1, 0, 2, 0, 3]);
 589 }
 590
 591 #[test]
 592 fn test_join() {
 593     let v: [Vec<i32>; 0] = [];
 594     assert_eq!(v.join(&0), []);
 595     assert_eq!([vec![1], vec![2, 3]].join(&0), [1, 0, 2, 3]);
 596     assert_eq!([vec![1], vec![2], vec![3]].join(&0), [1, 0, 2, 0, 3]);
 597
 598     let v: [&[_]; 2] = [&[1], &[2, 3]];
 599     assert_eq!(v.join(&0), [1, 0, 2, 3]);
 600     let v: [&[_]; 3] = [&[1], &[2], &[3]];
 601     assert_eq!(v.join(&0), [1, 0, 2, 0, 3]);
 602 }
 603
 604 #[test]
 605 fn test_join_nocopy() {
 606     let v: [String; 0] = [];
 607     assert_eq!(v.join(","), "");
 608     assert_eq!(["a".to_string(), "ab".into()].join(","), "a,ab");
 609     assert_eq!(["a".to_string(), "ab".into(), "abc".into()].join(","), "a,ab,abc");
 610     assert_eq!(["a".to_string(), "ab".into(), "".into()].join(","), "a,ab,");
 611 }
 612
 613 #[test]
 614 fn test_insert() {
 615     let mut a = vec![1, 2, 4];
 616     a.insert(2, 3);
 617     assert_eq!(a, [1, 2, 3, 4]);
 618
 619     let mut a = vec![1, 2, 3];
 620     a.insert(0, 0);
 621     assert_eq!(a, [0, 1, 2, 3]);
 622
 623     let mut a = vec![1, 2, 3];
 624     a.insert(3, 4);
 625     assert_eq!(a, [1, 2, 3, 4]);
 626
 627     let mut a = vec![];
 628     a.insert(0, 1);
 629     assert_eq!(a, [1]);
 630 }
 631
 632 #[test]
 633 #[should_panic]
 634 fn test_insert_oob() {
 635     let mut a = vec![1, 2, 3];
 636     a.insert(4, 5);
 637 }
 638
 639 #[test]
 640 fn test_remove() {
 641     let mut a = vec![1, 2, 3, 4];
 642
 643     assert_eq!(a.remove(2), 3);
 644     assert_eq!(a, [1, 2, 4]);
 645
 646     assert_eq!(a.remove(2), 4);
 647     assert_eq!(a, [1, 2]);
 648
 649     assert_eq!(a.remove(0), 1);
 650     assert_eq!(a, [2]);
 651
 652     assert_eq!(a.remove(0), 2);
 653     assert_eq!(a, []);
 654 }
 655
 656 #[test]
 657 #[should_panic]
 658 fn test_remove_fail() {
 659     let mut a = vec![1];
 660     let _ = a.remove(0);
 661     let _ = a.remove(0);
 662 }
 663
 664 #[test]
 665 fn test_capacity() {
 666     let mut v = vec![0];
 667     v.reserve_exact(10);
 668     assert!(v.capacity() >= 11);
 669 }
 670
 671 #[test]
 672 fn test_slice_2() {
 673     let v = vec![1, 2, 3, 4, 5];
 674     let v = &v[1..3];
 675     assert_eq!(v.len(), 2);
 676     assert_eq!(v[0], 2);
 677     assert_eq!(v[1], 3);
 678 }
 679
 680 macro_rules! assert_order {
 681     (Greater, $a:expr, $b:expr) => {
 682         assert_eq!($a.cmp($b), Greater);
 683         assert!($a > $b);
 684     };
 685     (Less, $a:expr, $b:expr) => {
 686         assert_eq!($a.cmp($b), Less);
 687         assert!($a < $b);
 688     };
 689     (Equal, $a:expr, $b:expr) => {
 690         assert_eq!($a.cmp($b), Equal);
 691         assert_eq!($a, $b);
 692     };
 693 }
 694
 695 #[test]
 696 fn test_total_ord_u8() {
 697     let c = &[1u8, 2, 3];
 698     assert_order!(Greater, &[1u8, 2, 3, 4][..], &c[..]);
 699     let c = &[1u8, 2, 3, 4];
 700     assert_order!(Less, &[1u8, 2, 3][..], &c[..]);
 701     let c = &[1u8, 2, 3, 6];
 702     assert_order!(Equal, &[1u8, 2, 3, 6][..], &c[..]);
 703     let c = &[1u8, 2, 3, 4, 5, 6];
 704     assert_order!(Less, &[1u8, 2, 3, 4, 5, 5, 5, 5][..], &c[..]);
 705     let c = &[1u8, 2, 3, 4];
 706     assert_order!(Greater, &[2u8, 2][..], &c[..]);
 707 }
 708
 709 #[test]
 710 fn test_total_ord_i32() {
 711     let c = &[1, 2, 3];
 712     assert_order!(Greater, &[1, 2, 3, 4][..], &c[..]);
 713     let c = &[1, 2, 3, 4];
 714     assert_order!(Less, &[1, 2, 3][..], &c[..]);
 715     let c = &[1, 2, 3, 6];
 716     assert_order!(Equal, &[1, 2, 3, 6][..], &c[..]);
 717     let c = &[1, 2, 3, 4, 5, 6];
 718     assert_order!(Less, &[1, 2, 3, 4, 5, 5, 5, 5][..], &c[..]);
 719     let c = &[1, 2, 3, 4];
 720     assert_order!(Greater, &[2, 2][..], &c[..]);
 721 }
 722
 723 #[test]
 724 fn test_iterator() {
 725     let xs = [1, 2, 5, 10, 11];
 726     let mut it = xs.iter();
 727     assert_eq!(it.size_hint(), (5, Some(5)));
 728     assert_eq!(it.next().unwrap(), &1);
 729     assert_eq!(it.size_hint(), (4, Some(4)));
 730     assert_eq!(it.next().unwrap(), &2);
 731     assert_eq!(it.size_hint(), (3, Some(3)));
 732     assert_eq!(it.next().unwrap(), &5);
 733     assert_eq!(it.size_hint(), (2, Some(2)));
 734     assert_eq!(it.next().unwrap(), &10);
 735     assert_eq!(it.size_hint(), (1, Some(1)));
 736     assert_eq!(it.next().unwrap(), &11);
 737     assert_eq!(it.size_hint(), (0, Some(0)));
 738     assert!(it.next().is_none());
 739 }
 740
 741 #[test]
 742 fn test_iter_size_hints() {
 743     let mut xs = [1, 2, 5, 10, 11];
 744     assert_eq!(xs.iter().size_hint(), (5, Some(5)));
 745     assert_eq!(xs.iter_mut().size_hint(), (5, Some(5)));
 746 }
 747
 748 #[test]
 749 fn test_iter_as_slice() {
 750     let xs = [1, 2, 5, 10, 11];
 751     let mut iter = xs.iter();
 752     assert_eq!(iter.as_slice(), &[1, 2, 5, 10, 11]);
 753     iter.next();
 754     assert_eq!(iter.as_slice(), &[2, 5, 10, 11]);
 755 }
 756
 757 #[test]
 758 fn test_iter_as_ref() {
 759     let xs = [1, 2, 5, 10, 11];
 760     let mut iter = xs.iter();
 761     assert_eq!(iter.as_ref(), &[1, 2, 5, 10, 11]);
 762     iter.next();
 763     assert_eq!(iter.as_ref(), &[2, 5, 10, 11]);
 764 }
 765
 766 #[test]
 767 fn test_iter_clone() {
 768     let xs = [1, 2, 5];
 769     let mut it = xs.iter();
 770     it.next();
 771     let mut jt = it.clone();
 772     assert_eq!(it.next(), jt.next());
 773     assert_eq!(it.next(), jt.next());
 774     assert_eq!(it.next(), jt.next());
 775 }
 776
 777 #[test]
 778 fn test_iter_is_empty() {
 779     let xs = [1, 2, 5, 10, 11];
 780     for i in 0..xs.len() {
 781         for j in i..xs.len() {
 782             assert_eq!(xs[i..j].iter().is_empty(), xs[i..j].is_empty());
 783         }
 784     }
 785 }
 786
 787 #[test]
 788 fn test_mut_iterator() {
 789     let mut xs = [1, 2, 3, 4, 5];
 790     for x in &mut xs {
 791         *x += 1;
 792     }
 793     assert!(xs == [2, 3, 4, 5, 6])
 794 }
 795
 796 #[test]
 797 fn test_rev_iterator() {
 798     let xs = [1, 2, 5, 10, 11];
 799     let ys = [11, 10, 5, 2, 1];
 800     let mut i = 0;
 801     for &x in xs.iter().rev() {
 802         assert_eq!(x, ys[i]);
 803         i += 1;
 804     }
 805     assert_eq!(i, 5);
 806 }
 807
 808 #[test]
 809 fn test_mut_rev_iterator() {
 810     let mut xs = [1, 2, 3, 4, 5];
 811     for (i, x) in xs.iter_mut().rev().enumerate() {
 812         *x += i;
 813     }
 814     assert!(xs == [5, 5, 5, 5, 5])
 815 }
 816
 817 #[test]
 818 fn test_move_iterator() {
 819     let xs = vec![1, 2, 3, 4, 5];
 820     assert_eq!(xs.into_iter().fold(0, |a: usize, b: usize| 10 * a + b), 12345);
 821 }
 822
 823 #[test]
 824 fn test_move_rev_iterator() {
 825     let xs = vec![1, 2, 3, 4, 5];
 826     assert_eq!(xs.into_iter().rev().fold(0, |a: usize, b: usize| 10 * a + b), 54321);
 827 }
 828
 829 #[test]
 830 fn test_splitator() {
 831     let xs = &[1, 2, 3, 4, 5];
 832
 833     let splits: &[&[_]] = &[&[1], &[3], &[5]];
 834     assert_eq!(xs.split(|x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 835     let splits: &[&[_]] = &[&[], &[2, 3, 4, 5]];
 836     assert_eq!(xs.split(|x| *x == 1).collect::<Vec<_>>(), splits);
 837     let splits: &[&[_]] = &[&[1, 2, 3, 4], &[]];
 838     assert_eq!(xs.split(|x| *x == 5).collect::<Vec<_>>(), splits);
 839     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 840     assert_eq!(xs.split(|x| *x == 10).collect::<Vec<_>>(), splits);
 841     let splits: &[&[_]] = &[&[], &[], &[], &[], &[], &[]];
 842     assert_eq!(xs.split(|_| true).collect::<Vec<&[i32]>>(), splits);
 843
 844     let xs: &[i32] = &[];
 845     let splits: &[&[i32]] = &[&[]];
 846     assert_eq!(xs.split(|x| *x == 5).collect::<Vec<&[i32]>>(), splits);
 847 }
 848
 849 #[test]
 850 fn test_splitator_inclusive() {
 851     let xs = &[1, 2, 3, 4, 5];
 852
 853     let splits: &[&[_]] = &[&[1, 2], &[3, 4], &[5]];
 854     assert_eq!(xs.split_inclusive(|x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 855     let splits: &[&[_]] = &[&[1], &[2, 3, 4, 5]];
 856     assert_eq!(xs.split_inclusive(|x| *x == 1).collect::<Vec<_>>(), splits);
 857     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 858     assert_eq!(xs.split_inclusive(|x| *x == 5).collect::<Vec<_>>(), splits);
 859     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 860     assert_eq!(xs.split_inclusive(|x| *x == 10).collect::<Vec<_>>(), splits);
 861     let splits: &[&[_]] = &[&[1], &[2], &[3], &[4], &[5]];
 862     assert_eq!(xs.split_inclusive(|_| true).collect::<Vec<&[i32]>>(), splits);
 863
 864     let xs: &[i32] = &[];
 865     let splits: &[&[i32]] = &[&[]];
 866     assert_eq!(xs.split_inclusive(|x| *x == 5).collect::<Vec<&[i32]>>(), splits);
 867 }
 868
 869 #[test]
 870 fn test_splitator_inclusive_reverse() {
 871     let xs = &[1, 2, 3, 4, 5];
 872
 873     let splits: &[&[_]] = &[&[5], &[3, 4], &[1, 2]];
 874     assert_eq!(xs.split_inclusive(|x| *x % 2 == 0).rev().collect::<Vec<_>>(), splits);
 875     let splits: &[&[_]] = &[&[2, 3, 4, 5], &[1]];
 876     assert_eq!(xs.split_inclusive(|x| *x == 1).rev().collect::<Vec<_>>(), splits);
 877     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 878     assert_eq!(xs.split_inclusive(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
 879     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 880     assert_eq!(xs.split_inclusive(|x| *x == 10).rev().collect::<Vec<_>>(), splits);
 881     let splits: &[&[_]] = &[&[5], &[4], &[3], &[2], &[1]];
 882     assert_eq!(xs.split_inclusive(|_| true).rev().collect::<Vec<_>>(), splits);
 883
 884     let xs: &[i32] = &[];
 885     let splits: &[&[i32]] = &[&[]];
 886     assert_eq!(xs.split_inclusive(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
 887 }
 888
 889 #[test]
 890 fn test_splitator_mut_inclusive() {
 891     let xs = &mut [1, 2, 3, 4, 5];
 892
 893     let splits: &[&[_]] = &[&[1, 2], &[3, 4], &[5]];
 894     assert_eq!(xs.split_inclusive_mut(|x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 895     let splits: &[&[_]] = &[&[1], &[2, 3, 4, 5]];
 896     assert_eq!(xs.split_inclusive_mut(|x| *x == 1).collect::<Vec<_>>(), splits);
 897     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 898     assert_eq!(xs.split_inclusive_mut(|x| *x == 5).collect::<Vec<_>>(), splits);
 899     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 900     assert_eq!(xs.split_inclusive_mut(|x| *x == 10).collect::<Vec<_>>(), splits);
 901     let splits: &[&[_]] = &[&[1], &[2], &[3], &[4], &[5]];
 902     assert_eq!(xs.split_inclusive_mut(|_| true).collect::<Vec<_>>(), splits);
 903
 904     let xs: &mut [i32] = &mut [];
 905     let splits: &[&[i32]] = &[&[]];
 906     assert_eq!(xs.split_inclusive_mut(|x| *x == 5).collect::<Vec<_>>(), splits);
 907 }
 908
 909 #[test]
 910 fn test_splitator_mut_inclusive_reverse() {
 911     let xs = &mut [1, 2, 3, 4, 5];
 912
 913     let splits: &[&[_]] = &[&[5], &[3, 4], &[1, 2]];
 914     assert_eq!(xs.split_inclusive_mut(|x| *x % 2 == 0).rev().collect::<Vec<_>>(), splits);
 915     let splits: &[&[_]] = &[&[2, 3, 4, 5], &[1]];
 916     assert_eq!(xs.split_inclusive_mut(|x| *x == 1).rev().collect::<Vec<_>>(), splits);
 917     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 918     assert_eq!(xs.split_inclusive_mut(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
 919     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 920     assert_eq!(xs.split_inclusive_mut(|x| *x == 10).rev().collect::<Vec<_>>(), splits);
 921     let splits: &[&[_]] = &[&[5], &[4], &[3], &[2], &[1]];
 922     assert_eq!(xs.split_inclusive_mut(|_| true).rev().collect::<Vec<_>>(), splits);
 923
 924     let xs: &mut [i32] = &mut [];
 925     let splits: &[&[i32]] = &[&[]];
 926     assert_eq!(xs.split_inclusive_mut(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
 927 }
 928
 929 #[test]
 930 fn test_splitnator() {
 931     let xs = &[1, 2, 3, 4, 5];
 932
 933     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 934     assert_eq!(xs.splitn(1, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 935     let splits: &[&[_]] = &[&[1], &[3, 4, 5]];
 936     assert_eq!(xs.splitn(2, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 937     let splits: &[&[_]] = &[&[], &[], &[], &[4, 5]];
 938     assert_eq!(xs.splitn(4, |_| true).collect::<Vec<_>>(), splits);
 939
 940     let xs: &[i32] = &[];
 941     let splits: &[&[i32]] = &[&[]];
 942     assert_eq!(xs.splitn(2, |x| *x == 5).collect::<Vec<_>>(), splits);
 943 }
 944
 945 #[test]
 946 fn test_splitnator_mut() {
 947     let xs = &mut [1, 2, 3, 4, 5];
 948
 949     let splits: &[&mut [_]] = &[&mut [1, 2, 3, 4, 5]];
 950     assert_eq!(xs.splitn_mut(1, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 951     let splits: &[&mut [_]] = &[&mut [1], &mut [3, 4, 5]];
 952     assert_eq!(xs.splitn_mut(2, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 953     let splits: &[&mut [_]] = &[&mut [], &mut [], &mut [], &mut [4, 5]];
 954     assert_eq!(xs.splitn_mut(4, |_| true).collect::<Vec<_>>(), splits);
 955
 956     let xs: &mut [i32] = &mut [];
 957     let splits: &[&mut [i32]] = &[&mut []];
 958     assert_eq!(xs.splitn_mut(2, |x| *x == 5).collect::<Vec<_>>(), splits);
 959 }
 960
 961 #[test]
 962 fn test_rsplitator() {
 963     let xs = &[1, 2, 3, 4, 5];
 964
 965     let splits: &[&[_]] = &[&[5], &[3], &[1]];
 966     assert_eq!(xs.split(|x| *x % 2 == 0).rev().collect::<Vec<_>>(), splits);
 967     let splits: &[&[_]] = &[&[2, 3, 4, 5], &[]];
 968     assert_eq!(xs.split(|x| *x == 1).rev().collect::<Vec<_>>(), splits);
 969     let splits: &[&[_]] = &[&[], &[1, 2, 3, 4]];
 970     assert_eq!(xs.split(|x| *x == 5).rev().collect::<Vec<_>>(), splits);
 971     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 972     assert_eq!(xs.split(|x| *x == 10).rev().collect::<Vec<_>>(), splits);
 973
 974     let xs: &[i32] = &[];
 975     let splits: &[&[i32]] = &[&[]];
 976     assert_eq!(xs.split(|x| *x == 5).rev().collect::<Vec<&[i32]>>(), splits);
 977 }
 978
 979 #[test]
 980 fn test_rsplitnator() {
 981     let xs = &[1, 2, 3, 4, 5];
 982
 983     let splits: &[&[_]] = &[&[1, 2, 3, 4, 5]];
 984     assert_eq!(xs.rsplitn(1, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 985     let splits: &[&[_]] = &[&[5], &[1, 2, 3]];
 986     assert_eq!(xs.rsplitn(2, |x| *x % 2 == 0).collect::<Vec<_>>(), splits);
 987     let splits: &[&[_]] = &[&[], &[], &[], &[1, 2]];
 988     assert_eq!(xs.rsplitn(4, |_| true).collect::<Vec<_>>(), splits);
 989
 990     let xs: &[i32] = &[];
 991     let splits: &[&[i32]] = &[&[]];
 992     assert_eq!(xs.rsplitn(2, |x| *x == 5).collect::<Vec<&[i32]>>(), splits);
 993     assert!(xs.rsplitn(0, |x| *x % 2 == 0).next().is_none());
 994 }
 995
 996 #[test]
 997 fn test_windowsator() {
 998     let v = &[1, 2, 3, 4];
 999
1000     let wins: &[&[_]] = &[&[1, 2], &[2, 3], &[3, 4]];
1001     assert_eq!(v.windows(2).collect::<Vec<_>>(), wins);
1002
1003     let wins: &[&[_]] = &[&[1, 2, 3], &[2, 3, 4]];
1004     assert_eq!(v.windows(3).collect::<Vec<_>>(), wins);
1005     assert!(v.windows(6).next().is_none());
1006
1007     let wins: &[&[_]] = &[&[3, 4], &[2, 3], &[1, 2]];
1008     assert_eq!(v.windows(2).rev().collect::<Vec<&[_]>>(), wins);
1009 }
1010
1011 #[test]
1012 #[should_panic]
1013 fn test_windowsator_0() {
1014     let v = &[1, 2, 3, 4];
1015     let _it = v.windows(0);
1016 }
1017
1018 #[test]
1019 fn test_chunksator() {
1020     let v = &[1, 2, 3, 4, 5];
1021
1022     assert_eq!(v.chunks(2).len(), 3);
1023
1024     let chunks: &[&[_]] = &[&[1, 2], &[3, 4], &[5]];
1025     assert_eq!(v.chunks(2).collect::<Vec<_>>(), chunks);
1026     let chunks: &[&[_]] = &[&[1, 2, 3], &[4, 5]];
1027     assert_eq!(v.chunks(3).collect::<Vec<_>>(), chunks);
1028     let chunks: &[&[_]] = &[&[1, 2, 3, 4, 5]];
1029     assert_eq!(v.chunks(6).collect::<Vec<_>>(), chunks);
1030
1031     let chunks: &[&[_]] = &[&[5], &[3, 4], &[1, 2]];
1032     assert_eq!(v.chunks(2).rev().collect::<Vec<_>>(), chunks);
1033 }
1034
1035 #[test]
1036 #[should_panic]
1037 fn test_chunksator_0() {
1038     let v = &[1, 2, 3, 4];
1039     let _it = v.chunks(0);
1040 }
1041
1042 #[test]
1043 fn test_chunks_exactator() {
1044     let v = &[1, 2, 3, 4, 5];
1045
1046     assert_eq!(v.chunks_exact(2).len(), 2);
1047
1048     let chunks: &[&[_]] = &[&[1, 2], &[3, 4]];
1049     assert_eq!(v.chunks_exact(2).collect::<Vec<_>>(), chunks);
1050     let chunks: &[&[_]] = &[&[1, 2, 3]];
1051     assert_eq!(v.chunks_exact(3).collect::<Vec<_>>(), chunks);
1052     let chunks: &[&[_]] = &[];
1053     assert_eq!(v.chunks_exact(6).collect::<Vec<_>>(), chunks);
1054
1055     let chunks: &[&[_]] = &[&[3, 4], &[1, 2]];
1056     assert_eq!(v.chunks_exact(2).rev().collect::<Vec<_>>(), chunks);
1057 }
1058
1059 #[test]
1060 #[should_panic]
1061 fn test_chunks_exactator_0() {
1062     let v = &[1, 2, 3, 4];
1063     let _it = v.chunks_exact(0);
1064 }
1065
1066 #[test]
1067 fn test_rchunksator() {
1068     let v = &[1, 2, 3, 4, 5];
1069
1070     assert_eq!(v.rchunks(2).len(), 3);
1071
1072     let chunks: &[&[_]] = &[&[4, 5], &[2, 3], &[1]];
1073     assert_eq!(v.rchunks(2).collect::<Vec<_>>(), chunks);
1074     let chunks: &[&[_]] = &[&[3, 4, 5], &[1, 2]];
1075     assert_eq!(v.rchunks(3).collect::<Vec<_>>(), chunks);
1076     let chunks: &[&[_]] = &[&[1, 2, 3, 4, 5]];
1077     assert_eq!(v.rchunks(6).collect::<Vec<_>>(), chunks);
1078
1079     let chunks: &[&[_]] = &[&[1], &[2, 3], &[4, 5]];
1080     assert_eq!(v.rchunks(2).rev().collect::<Vec<_>>(), chunks);
1081 }
1082
1083 #[test]
1084 #[should_panic]
1085 fn test_rchunksator_0() {
1086     let v = &[1, 2, 3, 4];
1087     let _it = v.rchunks(0);
1088 }
1089
1090 #[test]
1091 fn test_rchunks_exactator() {
1092     let v = &[1, 2, 3, 4, 5];
1093
1094     assert_eq!(v.rchunks_exact(2).len(), 2);
1095
1096     let chunks: &[&[_]] = &[&[4, 5], &[2, 3]];
1097     assert_eq!(v.rchunks_exact(2).collect::<Vec<_>>(), chunks);
1098     let chunks: &[&[_]] = &[&[3, 4, 5]];
1099     assert_eq!(v.rchunks_exact(3).collect::<Vec<_>>(), chunks);
1100     let chunks: &[&[_]] = &[];
1101     assert_eq!(v.rchunks_exact(6).collect::<Vec<_>>(), chunks);
1102
1103     let chunks: &[&[_]] = &[&[2, 3], &[4, 5]];
1104     assert_eq!(v.rchunks_exact(2).rev().collect::<Vec<_>>(), chunks);
1105 }
1106
1107 #[test]
1108 #[should_panic]
1109 fn test_rchunks_exactator_0() {
1110     let v = &[1, 2, 3, 4];
1111     let _it = v.rchunks_exact(0);
1112 }
1113
1114 #[test]
1115 fn test_reverse_part() {
1116     let mut values = [1, 2, 3, 4, 5];
1117     values[1..4].reverse();
1118     assert!(values == [1, 4, 3, 2, 5]);
1119 }
1120
1121 #[test]
1122 fn test_show() {
1123     macro_rules! test_show_vec {
1124         ($x:expr, $x_str:expr) => {{
1125             let (x, x_str) = ($x, $x_str);
1126             assert_eq!(format!("{:?}", x), x_str);
1127             assert_eq!(format!("{:?}", x), x_str);
1128         }};
1129     }
1130     let empty = Vec::<i32>::new();
1131     test_show_vec!(empty, "[]");
1132     test_show_vec!(vec![1], "[1]");
1133     test_show_vec!(vec![1, 2, 3], "[1, 2, 3]");
1134     test_show_vec!(vec![vec![], vec![1], vec![1, 1]], "[[], [1], [1, 1]]");
1135
1136     let empty_mut: &mut [i32] = &mut [];
1137     test_show_vec!(empty_mut, "[]");
1138     let v = &mut [1];
1139     test_show_vec!(v, "[1]");
1140     let v = &mut [1, 2, 3];
1141     test_show_vec!(v, "[1, 2, 3]");
1142     let v: &mut [&mut [_]] = &mut [&mut [], &mut [1], &mut [1, 1]];
1143     test_show_vec!(v, "[[], [1], [1, 1]]");
1144 }
1145
1146 #[test]
1147 fn test_vec_default() {
1148     macro_rules! t {
1149         ($ty:ty) => {{
1150             let v: $ty = Default::default();
1151             assert!(v.is_empty());
1152         }};
1153     }
1154
1155     t!(&[i32]);
1156     t!(Vec<i32>);
1157 }
1158
1159 #[test]
1160 #[should_panic]
1161 fn test_overflow_does_not_cause_segfault() {
1162     let mut v = vec![];
1163     v.reserve_exact(!0);
1164     v.push(1);
1165     v.push(2);
1166 }
1167
1168 #[test]
1169 #[should_panic]
1170 fn test_overflow_does_not_cause_segfault_managed() {
1171     let mut v = vec![Rc::new(1)];
1172     v.reserve_exact(!0);
1173     v.push(Rc::new(2));
1174 }
1175
1176 #[test]
1177 fn test_mut_split_at() {
1178     let mut values = [1, 2, 3, 4, 5];
1179     {
1180         let (left, right) = values.split_at_mut(2);
1181         {
1182             let left: &[_] = left;
1183             assert!(left[..left.len()] == [1, 2]);
1184         }
1185         for p in left {
1186             *p += 1;
1187         }
1188
1189         {
1190             let right: &[_] = right;
1191             assert!(right[..right.len()] == [3, 4, 5]);
1192         }
1193         for p in right {
1194             *p += 2;
1195         }
1196     }
1197
1198     assert!(values == [2, 3, 5, 6, 7]);
1199 }
1200
1201 #[derive(Clone, PartialEq)]
1202 struct Foo;
1203
1204 #[test]
1205 fn test_iter_zero_sized() {
1206     let mut v = vec![Foo, Foo, Foo];
1207     assert_eq!(v.len(), 3);
1208     let mut cnt = 0;
1209
1210     for f in &v {
1211         assert!(*f == Foo);
1212         cnt += 1;
1213     }
1214     assert_eq!(cnt, 3);
1215
1216     for f in &v[1..3] {
1217         assert!(*f == Foo);
1218         cnt += 1;
1219     }
1220     assert_eq!(cnt, 5);
1221
1222     for f in &mut v {
1223         assert!(*f == Foo);
1224         cnt += 1;
1225     }
1226     assert_eq!(cnt, 8);
1227
1228     for f in v {
1229         assert!(f == Foo);
1230         cnt += 1;
1231     }
1232     assert_eq!(cnt, 11);
1233
1234     let xs: [Foo; 3] = [Foo, Foo, Foo];
1235     cnt = 0;
1236     for f in &xs {
1237         assert!(*f == Foo);
1238         cnt += 1;
1239     }
1240     assert!(cnt == 3);
1241 }
1242
1243 #[test]
1244 fn test_shrink_to_fit() {
1245     let mut xs = vec![0, 1, 2, 3];
1246     for i in 4..100 {
1247         xs.push(i)
1248     }
1249     assert_eq!(xs.capacity(), 128);
1250     xs.shrink_to_fit();
1251     assert_eq!(xs.capacity(), 100);
1252     assert_eq!(xs, (0..100).collect::<Vec<_>>());
1253 }
1254
1255 #[test]
1256 fn test_starts_with() {
1257     assert!(b"foobar".starts_with(b"foo"));
1258     assert!(!b"foobar".starts_with(b"oob"));
1259     assert!(!b"foobar".starts_with(b"bar"));
1260     assert!(!b"foo".starts_with(b"foobar"));
1261     assert!(!b"bar".starts_with(b"foobar"));
1262     assert!(b"foobar".starts_with(b"foobar"));
1263     let empty: &[u8] = &[];
1264     assert!(empty.starts_with(empty));
1265     assert!(!empty.starts_with(b"foo"));
1266     assert!(b"foobar".starts_with(empty));
1267 }
1268
1269 #[test]
1270 fn test_ends_with() {
1271     assert!(b"foobar".ends_with(b"bar"));
1272     assert!(!b"foobar".ends_with(b"oba"));
1273     assert!(!b"foobar".ends_with(b"foo"));
1274     assert!(!b"foo".ends_with(b"foobar"));
1275     assert!(!b"bar".ends_with(b"foobar"));
1276     assert!(b"foobar".ends_with(b"foobar"));
1277     let empty: &[u8] = &[];
1278     assert!(empty.ends_with(empty));
1279     assert!(!empty.ends_with(b"foo"));
1280     assert!(b"foobar".ends_with(empty));
1281 }
1282
1283 #[test]
1284 fn test_mut_splitator() {
1285     let mut xs = [0, 1, 0, 2, 3, 0, 0, 4, 5, 0];
1286     assert_eq!(xs.split_mut(|x| *x == 0).count(), 6);
1287     for slice in xs.split_mut(|x| *x == 0) {
1288         slice.reverse();
1289     }
1290     assert!(xs == [0, 1, 0, 3, 2, 0, 0, 5, 4, 0]);
1291
1292     let mut xs = [0, 1, 0, 2, 3, 0, 0, 4, 5, 0, 6, 7];
1293     for slice in xs.split_mut(|x| *x == 0).take(5) {
1294         slice.reverse();
1295     }
1296     assert!(xs == [0, 1, 0, 3, 2, 0, 0, 5, 4, 0, 6, 7]);
1297 }
1298
1299 #[test]
1300 fn test_mut_splitator_rev() {
1301     let mut xs = [1, 2, 0, 3, 4, 0, 0, 5, 6, 0];
1302     for slice in xs.split_mut(|x| *x == 0).rev().take(4) {
1303         slice.reverse();
1304     }
1305     assert!(xs == [1, 2, 0, 4, 3, 0, 0, 6, 5, 0]);
1306 }
1307
1308 #[test]
1309 fn test_get_mut() {
1310     let mut v = [0, 1, 2];
1311     assert_eq!(v.get_mut(3), None);
1312     v.get_mut(1).map(|e| *e = 7);
1313     assert_eq!(v[1], 7);
1314     let mut x = 2;
1315     assert_eq!(v.get_mut(2), Some(&mut x));
1316 }
1317
1318 #[test]
1319 fn test_mut_chunks() {
1320     let mut v = [0, 1, 2, 3, 4, 5, 6];
1321     assert_eq!(v.chunks_mut(3).len(), 3);
1322     for (i, chunk) in v.chunks_mut(3).enumerate() {
1323         for x in chunk {
1324             *x = i as u8;
1325         }
1326     }
1327     let result = [0, 0, 0, 1, 1, 1, 2];
1328     assert_eq!(v, result);
1329 }
1330
1331 #[test]
1332 fn test_mut_chunks_rev() {
1333     let mut v = [0, 1, 2, 3, 4, 5, 6];
1334     for (i, chunk) in v.chunks_mut(3).rev().enumerate() {
1335         for x in chunk {
1336             *x = i as u8;
1337         }
1338     }
1339     let result = [2, 2, 2, 1, 1, 1, 0];
1340     assert_eq!(v, result);
1341 }
1342
1343 #[test]
1344 #[should_panic]
1345 fn test_mut_chunks_0() {
1346     let mut v = [1, 2, 3, 4];
1347     let _it = v.chunks_mut(0);
1348 }
1349
1350 #[test]
1351 fn test_mut_chunks_exact() {
1352     let mut v = [0, 1, 2, 3, 4, 5, 6];
1353     assert_eq!(v.chunks_exact_mut(3).len(), 2);
1354     for (i, chunk) in v.chunks_exact_mut(3).enumerate() {
1355         for x in chunk {
1356             *x = i as u8;
1357         }
1358     }
1359     let result = [0, 0, 0, 1, 1, 1, 6];
1360     assert_eq!(v, result);
1361 }
1362
1363 #[test]
1364 fn test_mut_chunks_exact_rev() {
1365     let mut v = [0, 1, 2, 3, 4, 5, 6];
1366     for (i, chunk) in v.chunks_exact_mut(3).rev().enumerate() {
1367         for x in chunk {
1368             *x = i as u8;
1369         }
1370     }
1371     let result = [1, 1, 1, 0, 0, 0, 6];
1372     assert_eq!(v, result);
1373 }
1374
1375 #[test]
1376 #[should_panic]
1377 fn test_mut_chunks_exact_0() {
1378     let mut v = [1, 2, 3, 4];
1379     let _it = v.chunks_exact_mut(0);
1380 }
1381
1382 #[test]
1383 fn test_mut_rchunks() {
1384     let mut v = [0, 1, 2, 3, 4, 5, 6];
1385     assert_eq!(v.rchunks_mut(3).len(), 3);
1386     for (i, chunk) in v.rchunks_mut(3).enumerate() {
1387         for x in chunk {
1388             *x = i as u8;
1389         }
1390     }
1391     let result = [2, 1, 1, 1, 0, 0, 0];
1392     assert_eq!(v, result);
1393 }
1394
1395 #[test]
1396 fn test_mut_rchunks_rev() {
1397     let mut v = [0, 1, 2, 3, 4, 5, 6];
1398     for (i, chunk) in v.rchunks_mut(3).rev().enumerate() {
1399         for x in chunk {
1400             *x = i as u8;
1401         }
1402     }
1403     let result = [0, 1, 1, 1, 2, 2, 2];
1404     assert_eq!(v, result);
1405 }
1406
1407 #[test]
1408 #[should_panic]
1409 fn test_mut_rchunks_0() {
1410     let mut v = [1, 2, 3, 4];
1411     let _it = v.rchunks_mut(0);
1412 }
1413
1414 #[test]
1415 fn test_mut_rchunks_exact() {
1416     let mut v = [0, 1, 2, 3, 4, 5, 6];
1417     assert_eq!(v.rchunks_exact_mut(3).len(), 2);
1418     for (i, chunk) in v.rchunks_exact_mut(3).enumerate() {
1419         for x in chunk {
1420             *x = i as u8;
1421         }
1422     }
1423     let result = [0, 1, 1, 1, 0, 0, 0];
1424     assert_eq!(v, result);
1425 }
1426
1427 #[test]
1428 fn test_mut_rchunks_exact_rev() {
1429     let mut v = [0, 1, 2, 3, 4, 5, 6];
1430     for (i, chunk) in v.rchunks_exact_mut(3).rev().enumerate() {
1431         for x in chunk {
1432             *x = i as u8;
1433         }
1434     }
1435     let result = [0, 0, 0, 0, 1, 1, 1];
1436     assert_eq!(v, result);
1437 }
1438
1439 #[test]
1440 #[should_panic]
1441 fn test_mut_rchunks_exact_0() {
1442     let mut v = [1, 2, 3, 4];
1443     let _it = v.rchunks_exact_mut(0);
1444 }
1445
1446 #[test]
1447 fn test_mut_last() {
1448     let mut x = [1, 2, 3, 4, 5];
1449     let h = x.last_mut();
1450     assert_eq!(*h.unwrap(), 5);
1451
1452     let y: &mut [i32] = &mut [];
1453     assert!(y.last_mut().is_none());
1454 }
1455
1456 #[test]
1457 fn test_to_vec() {
1458     let xs: Box<_> = box [1, 2, 3];
1459     let ys = xs.to_vec();
1460     assert_eq!(ys, [1, 2, 3]);
1461 }
1462
1463 #[test]
1464 fn test_in_place_iterator_specialization() {
1465     let src: Box<[usize]> = box [1, 2, 3];
1466     let src_ptr = src.as_ptr();
1467     let sink: Box<_> = src.into_vec().into_iter().map(std::convert::identity).collect();
1468     let sink_ptr = sink.as_ptr();
1469     assert_eq!(src_ptr, sink_ptr);
1470 }
1471
1472 #[test]
1473 fn test_box_slice_clone() {
1474     let data = vec![vec![0, 1], vec![0], vec![1]];
1475     let data2 = data.clone().into_boxed_slice().clone().to_vec();
1476
1477     assert_eq!(data, data2);
1478 }
1479
1480 #[test]
1481 #[allow(unused_must_use)] // here, we care about the side effects of `.clone()`
1482 #[cfg_attr(target_os = "emscripten", ignore)]
1483 fn test_box_slice_clone_panics() {
1484     use std::sync::atomic::{AtomicUsize, Ordering};
1485     use std::sync::Arc;
1486
1487     struct Canary {
1488         count: Arc<AtomicUsize>,
1489         panics: bool,
1490     }
1491
1492     impl Drop for Canary {
1493         fn drop(&mut self) {
1494             self.count.fetch_add(1, Ordering::SeqCst);
1495         }
1496     }
1497
1498     impl Clone for Canary {
1499         fn clone(&self) -> Self {
1500             if self.panics {
1501                 panic!()
1502             }
1503
1504             Canary { count: self.count.clone(), panics: self.panics }
1505         }
1506     }
1507
1508     let drop_count = Arc::new(AtomicUsize::new(0));
1509     let canary = Canary { count: drop_count.clone(), panics: false };
1510     let panic = Canary { count: drop_count.clone(), panics: true };
1511
1512     std::panic::catch_unwind(move || {
1513         // When xs is dropped, +5.
1514         let xs =
1515             vec![canary.clone(), canary.clone(), canary.clone(), panic, canary].into_boxed_slice();
1516
1517         // When panic is cloned, +3.
1518         xs.clone();
1519     })
1520     .unwrap_err();
1521
1522     // Total = 8
1523     assert_eq!(drop_count.load(Ordering::SeqCst), 8);
1524 }
1525
1526 #[test]
1527 fn test_copy_from_slice() {
1528     let src = [0, 1, 2, 3, 4, 5];
1529     let mut dst = [0; 6];
1530     dst.copy_from_slice(&src);
1531     assert_eq!(src, dst)
1532 }
1533
1534 #[test]
1535 #[should_panic(expected = "source slice length (4) does not match destination slice length (5)")]
1536 fn test_copy_from_slice_dst_longer() {
1537     let src = [0, 1, 2, 3];
1538     let mut dst = [0; 5];
1539     dst.copy_from_slice(&src);
1540 }
1541
1542 #[test]
1543 #[should_panic(expected = "source slice length (4) does not match destination slice length (3)")]
1544 fn test_copy_from_slice_dst_shorter() {
1545     let src = [0, 1, 2, 3];
1546     let mut dst = [0; 3];
1547     dst.copy_from_slice(&src);
1548 }
1549
1550 const MAX_LEN: usize = 80;
1551
1552 static DROP_COUNTS: [AtomicUsize; MAX_LEN] = [
1553     // FIXME(RFC 1109): AtomicUsize is not Copy.
1554     AtomicUsize::new(0),
1555     AtomicUsize::new(0),
1556     AtomicUsize::new(0),
1557     AtomicUsize::new(0),
1558     AtomicUsize::new(0),
1559     AtomicUsize::new(0),
1560     AtomicUsize::new(0),
1561     AtomicUsize::new(0),
1562     AtomicUsize::new(0),
1563     AtomicUsize::new(0),
1564     AtomicUsize::new(0),
1565     AtomicUsize::new(0),
1566     AtomicUsize::new(0),
1567     AtomicUsize::new(0),
1568     AtomicUsize::new(0),
1569     AtomicUsize::new(0),
1570     AtomicUsize::new(0),
1571     AtomicUsize::new(0),
1572     AtomicUsize::new(0),
1573     AtomicUsize::new(0),
1574     AtomicUsize::new(0),
1575     AtomicUsize::new(0),
1576     AtomicUsize::new(0),
1577     AtomicUsize::new(0),
1578     AtomicUsize::new(0),
1579     AtomicUsize::new(0),
1580     AtomicUsize::new(0),
1581     AtomicUsize::new(0),
1582     AtomicUsize::new(0),
1583     AtomicUsize::new(0),
1584     AtomicUsize::new(0),
1585     AtomicUsize::new(0),
1586     AtomicUsize::new(0),
1587     AtomicUsize::new(0),
1588     AtomicUsize::new(0),
1589     AtomicUsize::new(0),
1590     AtomicUsize::new(0),
1591     AtomicUsize::new(0),
1592     AtomicUsize::new(0),
1593     AtomicUsize::new(0),
1594     AtomicUsize::new(0),
1595     AtomicUsize::new(0),
1596     AtomicUsize::new(0),
1597     AtomicUsize::new(0),
1598     AtomicUsize::new(0),
1599     AtomicUsize::new(0),
1600     AtomicUsize::new(0),
1601     AtomicUsize::new(0),
1602     AtomicUsize::new(0),
1603     AtomicUsize::new(0),
1604     AtomicUsize::new(0),
1605     AtomicUsize::new(0),
1606     AtomicUsize::new(0),
1607     AtomicUsize::new(0),
1608     AtomicUsize::new(0),
1609     AtomicUsize::new(0),
1610     AtomicUsize::new(0),
1611     AtomicUsize::new(0),
1612     AtomicUsize::new(0),
1613     AtomicUsize::new(0),
1614     AtomicUsize::new(0),
1615     AtomicUsize::new(0),
1616     AtomicUsize::new(0),
1617     AtomicUsize::new(0),
1618     AtomicUsize::new(0),
1619     AtomicUsize::new(0),
1620     AtomicUsize::new(0),
1621     AtomicUsize::new(0),
1622     AtomicUsize::new(0),
1623     AtomicUsize::new(0),
1624     AtomicUsize::new(0),
1625     AtomicUsize::new(0),
1626     AtomicUsize::new(0),
1627     AtomicUsize::new(0),
1628     AtomicUsize::new(0),
1629     AtomicUsize::new(0),
1630     AtomicUsize::new(0),
1631     AtomicUsize::new(0),
1632     AtomicUsize::new(0),
1633     AtomicUsize::new(0),
1634 ];
1635
1636 static VERSIONS: AtomicUsize = AtomicUsize::new(0);
1637
1638 #[derive(Clone, Eq)]
1639 struct DropCounter {
1640     x: u32,
1641     id: usize,
1642     version: Cell<usize>,
1643 }
1644
1645 impl PartialEq for DropCounter {
1646     fn eq(&self, other: &Self) -> bool {
1647         self.partial_cmp(other) == Some(Ordering::Equal)
1648     }
1649 }
1650
1651 impl PartialOrd for DropCounter {
1652     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1653         self.version.set(self.version.get() + 1);
1654         other.version.set(other.version.get() + 1);
1655         VERSIONS.fetch_add(2, Relaxed);
1656         self.x.partial_cmp(&other.x)
1657     }
1658 }
1659
1660 impl Ord for DropCounter {
1661     fn cmp(&self, other: &Self) -> Ordering {
1662         self.partial_cmp(other).unwrap()
1663     }
1664 }
1665
1666 impl Drop for DropCounter {
1667     fn drop(&mut self) {
1668         DROP_COUNTS[self.id].fetch_add(1, Relaxed);
1669         VERSIONS.fetch_sub(self.version.get(), Relaxed);
1670     }
1671 }
1672
1673 macro_rules! test {
1674     ($input:ident, $func:ident) => {
1675         let len = $input.len();
1676
1677         // Work out the total number of comparisons required to sort
1678         // this array...
1679         let mut count = 0usize;
1680         $input.to_owned().$func(|a, b| {
1681             count += 1;
1682             a.cmp(b)
1683         });
1684
1685         // ... and then panic on each and every single one.
1686         for panic_countdown in 0..count {
1687             // Refresh the counters.
1688             VERSIONS.store(0, Relaxed);
1689             for i in 0..len {
1690                 DROP_COUNTS[i].store(0, Relaxed);
1691             }
1692
1693             let v = $input.to_owned();
1694             let _ = std::panic::catch_unwind(move || {
1695                 let mut v = v;
1696                 let mut panic_countdown = panic_countdown;
1697                 v.$func(|a, b| {
1698                     if panic_countdown == 0 {
1699                         SILENCE_PANIC.with(|s| s.set(true));
1700                         panic!();
1701                     }
1702                     panic_countdown -= 1;
1703                     a.cmp(b)
1704                 })
1705             });
1706
1707             // Check that the number of things dropped is exactly
1708             // what we expect (i.e., the contents of `v`).
1709             for (i, c) in DROP_COUNTS.iter().enumerate().take(len) {
1710                 let count = c.load(Relaxed);
1711                 assert!(count == 1, "found drop count == {} for i == {}, len == {}", count, i, len);
1712             }
1713
1714             // Check that the most recent versions of values were dropped.
1715             assert_eq!(VERSIONS.load(Relaxed), 0);
1716         }
1717     };
1718 }
1719
1720 thread_local!(static SILENCE_PANIC: Cell<bool> = Cell::new(false));
1721
1722 #[test]
1723 #[cfg_attr(target_os = "emscripten", ignore)] // no threads
1724 fn panic_safe() {
1725     let prev = panic::take_hook();
1726     panic::set_hook(Box::new(move |info| {
1727         if !SILENCE_PANIC.with(|s| s.get()) {
1728             prev(info);
1729         }
1730     }));
1731
1732     let mut rng = thread_rng();
1733
1734     // Miri is too slow (but still need to `chain` to make the types match)
1735     let lens = if cfg!(miri) { (1..10).chain(0..0) } else { (1..20).chain(70..MAX_LEN) };
1736     let moduli: &[u32] = if cfg!(miri) { &[5] } else { &[5, 20, 50] };
1737
1738     for len in lens {
1739         for &modulus in moduli {
1740             for &has_runs in &[false, true] {
1741                 let mut input = (0..len)
1742                     .map(|id| DropCounter {
1743                         x: rng.next_u32() % modulus,
1744                         id: id,
1745                         version: Cell::new(0),
1746                     })
1747                     .collect::<Vec<_>>();
1748
1749                 if has_runs {
1750                     for c in &mut input {
1751                         c.x = c.id as u32;
1752                     }
1753
1754                     for _ in 0..5 {
1755                         let a = rng.gen::<usize>() % len;
1756                         let b = rng.gen::<usize>() % len;
1757                         if a < b {
1758                             input[a..b].reverse();
1759                         } else {
1760                             input.swap(a, b);
1761                         }
1762                     }
1763                 }
1764
1765                 test!(input, sort_by);
1766                 test!(input, sort_unstable_by);
1767             }
1768         }
1769     }
1770
1771     // Set default panic hook again.
1772     drop(panic::take_hook());
1773 }
1774
1775 #[test]
1776 fn repeat_generic_slice() {
1777     assert_eq!([1, 2].repeat(2), vec![1, 2, 1, 2]);
1778     assert_eq!([1, 2, 3, 4].repeat(0), vec![]);
1779     assert_eq!([1, 2, 3, 4].repeat(1), vec![1, 2, 3, 4]);
1780     assert_eq!([1, 2, 3, 4].repeat(3), vec![1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]);
1781 }
1782
1783 #[test]
1784 #[allow(unreachable_patterns)]
1785 fn subslice_patterns() {
1786     // This test comprehensively checks the passing static and dynamic semantics
1787     // of subslice patterns `..`, `x @ ..`, `ref x @ ..`, and `ref mut @ ..`
1788     // in slice patterns `[$($pat), $(,)?]` .
1789
1790     #[derive(PartialEq, Debug, Clone)]
1791     struct N(u8);
1792
1793     macro_rules! n {
1794         ($($e:expr),* $(,)?) => {
1795             [$(N($e)),*]
1796         }
1797     }
1798
1799     macro_rules! c {
1800         ($inp:expr, $typ:ty, $out:expr $(,)?) => {
1801             assert_eq!($out, identity::<$typ>($inp))
1802         };
1803     }
1804
1805     macro_rules! m {
1806         ($e:expr, $p:pat => $b:expr) => {
1807             match $e {
1808                 $p => $b,
1809                 _ => panic!(),
1810             }
1811         };
1812     }
1813
1814     // == Slices ==
1815
1816     // Matching slices using `ref` patterns:
1817     let mut v = vec![N(0), N(1), N(2), N(3), N(4)];
1818     let mut vc = (0..=4).collect::<Vec<u8>>();
1819
1820     let [..] = v[..]; // Always matches.
1821     m!(v[..], [N(0), ref sub @ .., N(4)] => c!(sub, &[N], n![1, 2, 3]));
1822     m!(v[..], [N(0), ref sub @ ..] => c!(sub, &[N], n![1, 2, 3, 4]));
1823     m!(v[..], [ref sub @ .., N(4)] => c!(sub, &[N], n![0, 1, 2, 3]));
1824     m!(v[..], [ref sub @ .., _, _, _, _, _] => c!(sub, &[N], &n![] as &[N]));
1825     m!(v[..], [_, _, _, _, _, ref sub @ ..] => c!(sub, &[N], &n![] as &[N]));
1826     m!(vc[..], [x, .., y] => c!((x, y), (u8, u8), (0, 4)));
1827
1828     // Matching slices using `ref mut` patterns:
1829     let [..] = v[..]; // Always matches.
1830     m!(v[..], [N(0), ref mut sub @ .., N(4)] => c!(sub, &mut [N], n![1, 2, 3]));
1831     m!(v[..], [N(0), ref mut sub @ ..] => c!(sub, &mut [N], n![1, 2, 3, 4]));
1832     m!(v[..], [ref mut sub @ .., N(4)] => c!(sub, &mut [N], n![0, 1, 2, 3]));
1833     m!(v[..], [ref mut sub @ .., _, _, _, _, _] => c!(sub, &mut [N], &mut n![] as &mut [N]));
1834     m!(v[..], [_, _, _, _, _, ref mut sub @ ..] => c!(sub, &mut [N], &mut n![] as &mut [N]));
1835     m!(vc[..], [x, .., y] => c!((x, y), (u8, u8), (0, 4)));
1836
1837     // Matching slices using default binding modes (&):
1838     let [..] = &v[..]; // Always matches.
1839     m!(&v[..], [N(0), sub @ .., N(4)] => c!(sub, &[N], n![1, 2, 3]));
1840     m!(&v[..], [N(0), sub @ ..] => c!(sub, &[N], n![1, 2, 3, 4]));
1841     m!(&v[..], [sub @ .., N(4)] => c!(sub, &[N], n![0, 1, 2, 3]));
1842     m!(&v[..], [sub @ .., _, _, _, _, _] => c!(sub, &[N], &n![] as &[N]));
1843     m!(&v[..], [_, _, _, _, _, sub @ ..] => c!(sub, &[N], &n![] as &[N]));
1844     m!(&vc[..], [x, .., y] => c!((x, y), (&u8, &u8), (&0, &4)));
1845
1846     // Matching slices using default binding modes (&mut):
1847     let [..] = &mut v[..]; // Always matches.
1848     m!(&mut v[..], [N(0), sub @ .., N(4)] => c!(sub, &mut [N], n![1, 2, 3]));
1849     m!(&mut v[..], [N(0), sub @ ..] => c!(sub, &mut [N], n![1, 2, 3, 4]));
1850     m!(&mut v[..], [sub @ .., N(4)] => c!(sub, &mut [N], n![0, 1, 2, 3]));
1851     m!(&mut v[..], [sub @ .., _, _, _, _, _] => c!(sub, &mut [N], &mut n![] as &mut [N]));
1852     m!(&mut v[..], [_, _, _, _, _, sub @ ..] => c!(sub, &mut [N], &mut n![] as &mut [N]));
1853     m!(&mut vc[..], [x, .., y] => c!((x, y), (&mut u8, &mut u8), (&mut 0, &mut 4)));
1854
1855     // == Arrays ==
1856     let mut v = n![0, 1, 2, 3, 4];
1857     let vc = [0, 1, 2, 3, 4];
1858
1859     // Matching arrays by value:
1860     m!(v.clone(), [N(0), sub @ .., N(4)] => c!(sub, [N; 3], n![1, 2, 3]));
1861     m!(v.clone(), [N(0), sub @ ..] => c!(sub, [N; 4], n![1, 2, 3, 4]));
1862     m!(v.clone(), [sub @ .., N(4)] => c!(sub, [N; 4], n![0, 1, 2, 3]));
1863     m!(v.clone(), [sub @ .., _, _, _, _, _] => c!(sub, [N; 0], n![] as [N; 0]));
1864     m!(v.clone(), [_, _, _, _, _, sub @ ..] => c!(sub, [N; 0], n![] as [N; 0]));
1865     m!(v.clone(), [x, .., y] => c!((x, y), (N, N), (N(0), N(4))));
1866     m!(v.clone(), [..] => ());
1867
1868     // Matching arrays by ref patterns:
1869     m!(v, [N(0), ref sub @ .., N(4)] => c!(sub, &[N; 3], &n![1, 2, 3]));
1870     m!(v, [N(0), ref sub @ ..] => c!(sub, &[N; 4], &n![1, 2, 3, 4]));
1871     m!(v, [ref sub @ .., N(4)] => c!(sub, &[N; 4], &n![0, 1, 2, 3]));
1872     m!(v, [ref sub @ .., _, _, _, _, _] => c!(sub, &[N; 0], &n![] as &[N; 0]));
1873     m!(v, [_, _, _, _, _, ref sub @ ..] => c!(sub, &[N; 0], &n![] as &[N; 0]));
1874     m!(vc, [x, .., y] => c!((x, y), (u8, u8), (0, 4)));
1875
1876     // Matching arrays by ref mut patterns:
1877     m!(v, [N(0), ref mut sub @ .., N(4)] => c!(sub, &mut [N; 3], &mut n![1, 2, 3]));
1878     m!(v, [N(0), ref mut sub @ ..] => c!(sub, &mut [N; 4], &mut n![1, 2, 3, 4]));
1879     m!(v, [ref mut sub @ .., N(4)] => c!(sub, &mut [N; 4], &mut n![0, 1, 2, 3]));
1880     m!(v, [ref mut sub @ .., _, _, _, _, _] => c!(sub, &mut [N; 0], &mut n![] as &mut [N; 0]));
1881     m!(v, [_, _, _, _, _, ref mut sub @ ..] => c!(sub, &mut [N; 0], &mut n![] as &mut [N; 0]));
1882
1883     // Matching arrays by default binding modes (&):
1884     m!(&v, [N(0), sub @ .., N(4)] => c!(sub, &[N; 3], &n![1, 2, 3]));
1885     m!(&v, [N(0), sub @ ..] => c!(sub, &[N; 4], &n![1, 2, 3, 4]));
1886     m!(&v, [sub @ .., N(4)] => c!(sub, &[N; 4], &n![0, 1, 2, 3]));
1887     m!(&v, [sub @ .., _, _, _, _, _] => c!(sub, &[N; 0], &n![] as &[N; 0]));
1888     m!(&v, [_, _, _, _, _, sub @ ..] => c!(sub, &[N; 0], &n![] as &[N; 0]));
1889     m!(&v, [..] => ());
1890     m!(&v, [x, .., y] => c!((x, y), (&N, &N), (&N(0), &N(4))));
1891
1892     // Matching arrays by default binding modes (&mut):
1893     m!(&mut v, [N(0), sub @ .., N(4)] => c!(sub, &mut [N; 3], &mut n![1, 2, 3]));
1894     m!(&mut v, [N(0), sub @ ..] => c!(sub, &mut [N; 4], &mut n![1, 2, 3, 4]));
1895     m!(&mut v, [sub @ .., N(4)] => c!(sub, &mut [N; 4], &mut n![0, 1, 2, 3]));
1896     m!(&mut v, [sub @ .., _, _, _, _, _] => c!(sub, &mut [N; 0], &mut n![] as &[N; 0]));
1897     m!(&mut v, [_, _, _, _, _, sub @ ..] => c!(sub, &mut [N; 0], &mut n![] as &[N; 0]));
1898     m!(&mut v, [..] => ());
1899     m!(&mut v, [x, .., y] => c!((x, y), (&mut N, &mut N), (&mut N(0), &mut N(4))));
1900 }
1901
1902 #[test]
1903 fn test_group_by() {
1904     let slice = &[1, 1, 1, 3, 3, 2, 2, 2, 1, 0];
1905
1906     let mut iter = slice.group_by(|a, b| a == b);
1907     assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
1908     assert_eq!(iter.next(), Some(&[3, 3][..]));
1909     assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
1910     assert_eq!(iter.next(), Some(&[1][..]));
1911     assert_eq!(iter.next(), Some(&[0][..]));
1912     assert_eq!(iter.next(), None);
1913
1914     let mut iter = slice.group_by(|a, b| a == b);
1915     assert_eq!(iter.next_back(), Some(&[0][..]));
1916     assert_eq!(iter.next_back(), Some(&[1][..]));
1917     assert_eq!(iter.next_back(), Some(&[2, 2, 2][..]));
1918     assert_eq!(iter.next_back(), Some(&[3, 3][..]));
1919     assert_eq!(iter.next_back(), Some(&[1, 1, 1][..]));
1920     assert_eq!(iter.next_back(), None);
1921
1922     let mut iter = slice.group_by(|a, b| a == b);
1923     assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
1924     assert_eq!(iter.next_back(), Some(&[0][..]));
1925     assert_eq!(iter.next(), Some(&[3, 3][..]));
1926     assert_eq!(iter.next_back(), Some(&[1][..]));
1927     assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
1928     assert_eq!(iter.next_back(), None);
1929 }
1930
1931 #[test]
1932 fn test_group_by_mut() {
1933     let slice = &mut [1, 1, 1, 3, 3, 2, 2, 2, 1, 0];
1934
1935     let mut iter = slice.group_by_mut(|a, b| a == b);
1936     assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
1937     assert_eq!(iter.next(), Some(&mut [3, 3][..]));
1938     assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
1939     assert_eq!(iter.next(), Some(&mut [1][..]));
1940     assert_eq!(iter.next(), Some(&mut [0][..]));
1941     assert_eq!(iter.next(), None);
1942
1943     let mut iter = slice.group_by_mut(|a, b| a == b);
1944     assert_eq!(iter.next_back(), Some(&mut [0][..]));
1945     assert_eq!(iter.next_back(), Some(&mut [1][..]));
1946     assert_eq!(iter.next_back(), Some(&mut [2, 2, 2][..]));
1947     assert_eq!(iter.next_back(), Some(&mut [3, 3][..]));
1948     assert_eq!(iter.next_back(), Some(&mut [1, 1, 1][..]));
1949     assert_eq!(iter.next_back(), None);
1950
1951     let mut iter = slice.group_by_mut(|a, b| a == b);
1952     assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
1953     assert_eq!(iter.next_back(), Some(&mut [0][..]));
1954     assert_eq!(iter.next(), Some(&mut [3, 3][..]));
1955     assert_eq!(iter.next_back(), Some(&mut [1][..]));
1956     assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
1957     assert_eq!(iter.next_back(), None);
1958 }