diff options
| -rw-r--r-- | src/libcore/mem.rs | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs index 680a0f5b2c0..16d5fadc536 100644 --- a/src/libcore/mem.rs +++ b/src/libcore/mem.rs @@ -429,9 +429,11 @@ pub fn align_of_val<T: ?Sized>(val: &T) -> usize { /// Returns whether dropping values of type `T` matters. /// -/// This is purely an optimization hint, and may be implemented conservatively. -/// For instance, always returning `true` would be a valid implementation of -/// this function. +/// This is purely an optimization hint, and may be implemented conservatively: +/// it may return `true` for types that don't actually need to be dropped. +/// As such always returning `true` would be a valid implementation of +/// this function. However if this function actually returns `false`, then you +/// can be certain dropping `T` has no side effect. /// /// Low level implementations of things like collections, which need to manually /// drop their data, should use this function to avoid unnecessarily |