diff options
| author | Matthias Krüger <matthias.krueger@famsik.de> | 2024-02-11 23:19:09 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-02-11 23:19:09 +0100 |
| commit | 3d7d709925294ae6d7304242d21a3b5cd3676c15 (patch) | |
| tree | a8285e27ee414b991d0213851882900fde8aa8bf /library/core/src/ptr | |
| parent | 4c154a1a48f59f258c822fe81057608c13b9cd1a (diff) | |
| parent | aaa6d3bec2d08f425c844f5964782e1d6a1bbc88 (diff) | |
| download | rust-3d7d709925294ae6d7304242d21a3b5cd3676c15.tar.gz rust-3d7d709925294ae6d7304242d21a3b5cd3676c15.zip | |
Rollup merge of #120880 - RalfJung:vtable-fnptr-partialeq, r=cuviper
add note on comparing vtables / function pointers Fixes https://github.com/rust-lang/rust/issues/99388 Fixes https://github.com/rust-lang/rust/issues/117047
Diffstat (limited to 'library/core/src/ptr')
| -rw-r--r-- | library/core/src/ptr/metadata.rs | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/library/core/src/ptr/metadata.rs b/library/core/src/ptr/metadata.rs index a6a390db043..c7b0fe5694a 100644 --- a/library/core/src/ptr/metadata.rs +++ b/library/core/src/ptr/metadata.rs @@ -175,6 +175,11 @@ impl<T: ?Sized> Clone for PtrComponents<T> { /// /// It is possible to name this struct with a type parameter that is not a `dyn` trait object /// (for example `DynMetadata<u64>`) but not to obtain a meaningful value of that struct. +/// +/// Note that while this type implements `PartialEq`, comparing vtable pointers is unreliable: +/// pointers to vtables of the same type for the same trait can compare inequal (because vtables are +/// duplicated in multiple codegen units), and pointers to vtables of *different* types/traits can +/// compare equal (since identical vtables can be deduplicated within a codegen unit). #[lang = "dyn_metadata"] pub struct DynMetadata<Dyn: ?Sized> { vtable_ptr: &'static VTable, |