diff options
Diffstat (limited to 'src/libstd')
| -rw-r--r-- | src/libstd/collections/hash/map.rs | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs index 5fdc6056c68..e8ca2977241 100644 --- a/src/libstd/collections/hash/map.rs +++ b/src/libstd/collections/hash/map.rs @@ -667,8 +667,9 @@ impl<K, V, S> HashMap<K, V, S> /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn reserve(&mut self, additional: usize) { - let min_cap = self.len().checked_add(additional).expect("reserve overflow"); - if self.capacity() < min_cap { + let remaining = self.capacity() - self.len(); // this can't overflow + if remaining < additional { + let min_cap = self.len().checked_add(additional).expect("reserve overflow"); let raw_cap = self.resize_policy.raw_capacity(min_cap); self.resize(raw_cap); } |