diff options
| -rw-r--r-- | src/libcore/slice/mod.rs | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs index da4a56cfecd..59f71303200 100644 --- a/src/libcore/slice/mod.rs +++ b/src/libcore/slice/mod.rs @@ -119,7 +119,7 @@ impl<T> [T] { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn first(&self) -> Option<&T> { - if self.is_empty() { None } else { Some(&self[0]) } + self.get(0) } /// Returns a mutable pointer to the first element of the slice, or `None` if it is empty. @@ -137,7 +137,7 @@ impl<T> [T] { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn first_mut(&mut self) -> Option<&mut T> { - if self.is_empty() { None } else { Some(&mut self[0]) } + self.get_mut(0) } /// Returns the first and all the rest of the elements of the slice, or `None` if it is empty. @@ -239,7 +239,8 @@ impl<T> [T] { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn last(&self) -> Option<&T> { - if self.is_empty() { None } else { Some(&self[self.len() - 1]) } + let last_idx = self.len().checked_sub(1)?; + self.get(last_idx) } /// Returns a mutable pointer to the last item in the slice. @@ -257,9 +258,8 @@ impl<T> [T] { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn last_mut(&mut self) -> Option<&mut T> { - let len = self.len(); - if len == 0 { return None; } - Some(&mut self[len - 1]) + let last_idx = self.len().checked_sub(1)?; + self.get_mut(last_idx) } /// Returns a reference to an element or subslice depending on the type of |