diff options
Diffstat (limited to 'library/core/src/ptr/mod.rs')
| -rw-r--r-- | library/core/src/ptr/mod.rs | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs index ecbf4e66fa4..ff9fa48f311 100644 --- a/library/core/src/ptr/mod.rs +++ b/library/core/src/ptr/mod.rs @@ -441,10 +441,18 @@ mod mut_ptr; /// /// * `to_drop` must be [valid] for both reads and writes. /// -/// * `to_drop` must be properly aligned. +/// * `to_drop` must be properly aligned, even if `T` has size 0. /// -/// * The value `to_drop` points to must be valid for dropping, which may mean it must uphold -/// additional invariants - this is type-dependent. +/// * `to_drop` must be nonnull, even if `T` has size 0. +/// +/// * The value `to_drop` points to must be valid for dropping, which may mean +/// it must uphold additional invariants. These invariants depend on the type +/// of the value being dropped. For instance, when dropping a Box, the box's +/// pointer to the heap must be valid. +/// +/// * While `drop_in_place` is executing, the only way to access parts of +/// `to_drop` is through the `&mut self` references supplied to the +/// `Drop::drop` methods that `drop_in_place` invokes. /// /// Additionally, if `T` is not [`Copy`], using the pointed-to value after /// calling `drop_in_place` can cause undefined behavior. Note that `*to_drop = @@ -452,8 +460,6 @@ mod mut_ptr; /// again. [`write()`] can be used to overwrite data without causing it to be /// dropped. /// -/// Note that even if `T` has size `0`, the pointer must be non-null and properly aligned. -/// /// [valid]: self#safety /// /// # Examples |