diff options
| -rw-r--r-- | src/libcore/iter/adapters/mod.rs | 10 | ||||
| -rw-r--r-- | src/test/ui/iterators/skip-count-overflow.rs | 8 |
2 files changed, 16 insertions, 2 deletions
diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs index 6eb837ed0fe..5787b9174ed 100644 --- a/src/libcore/iter/adapters/mod.rs +++ b/src/libcore/iter/adapters/mod.rs @@ -1815,8 +1815,14 @@ where } #[inline] - fn count(self) -> usize { - self.iter.count().saturating_sub(self.n) + fn count(mut self) -> usize { + if self.n > 0 { + // nth(n) skips n+1 + if self.iter.nth(self.n - 1).is_none() { + return 0; + } + } + self.iter.count() } #[inline] diff --git a/src/test/ui/iterators/skip-count-overflow.rs b/src/test/ui/iterators/skip-count-overflow.rs new file mode 100644 index 00000000000..d8efc948664 --- /dev/null +++ b/src/test/ui/iterators/skip-count-overflow.rs @@ -0,0 +1,8 @@ +// run-pass +// only-32bit too impatient for 2⁶⁴ items +// compile-flags: -C overflow-checks -C opt-level=3 + +fn main() { + let i = (0..usize::max_value()).chain(0..10).skip(usize::max_value()); + assert_eq!(i.count(), 10); +} |