diff options
| author | Matthias Krüger <matthias.krueger@famsik.de> | 2024-05-30 10:23:07 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-05-30 10:23:07 +0200 |
| commit | 60c2d80482c932dd02cdbb74e5e97c173bc7262b (patch) | |
| tree | eee22e9255a6d50916c3398bc57dda89c1b54343 /library/core/src/ptr | |
| parent | 7ed5d469e8dac6a7381cd7300d0b420c5f0bf4c1 (diff) | |
| parent | 5c68a15e41a4e2fe792508ec130c3659b198db3d (diff) | |
Rollup merge of #125739 - RalfJung:drop-in-place-docs, r=workingjubilee
drop_in_place: weaken the claim of equivalence with drop(ptr.read()) The two are *not* semantically equivalent in all cases, so let's not be so definite about this. Fixes https://github.com/rust-lang/rust/issues/112015
Diffstat (limited to 'library/core/src/ptr')
| -rw-r--r-- | library/core/src/ptr/mod.rs | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs index 4213a9dedfe..8e3447d0b1b 100644 --- a/library/core/src/ptr/mod.rs +++ b/library/core/src/ptr/mod.rs @@ -450,8 +450,13 @@ mod mut_ptr; /// Executes the destructor (if any) of the pointed-to value. /// -/// This is semantically equivalent to calling [`ptr::read`] and discarding +/// This is almost the same as calling [`ptr::read`] and discarding /// the result, but has the following advantages: +// FIXME: say something more useful than "almost the same"? +// There are open questions here: `read` requires the value to be fully valid, e.g. if `T` is a +// `bool` it must be 0 or 1, if it is a reference then it must be dereferenceable. `drop_in_place` +// only requires that `*to_drop` be "valid for dropping" and we have not defined what that means. In +// Miri it currently (May 2024) requires nothing at all for types without drop glue. /// /// * It is *required* to use `drop_in_place` to drop unsized types like /// trait objects, because they can't be read out onto the stack and |