Guillaume Gomez ca222b85ff Rollup merge of #156104 - aobatact:try-as-dyn-unsized, r=oli-obk ...

Relax `T: Sized` bound on `try_as_dyn` / `try_as_dyn_mut`

`trait_info_of` already returns `None` for unsized types, so allowing `T: ?Sized` is sound and lets callers in generic contexts use these functions without a separate `Sized` bound. For unsized `T`, the function always returns `None`.

Tracking issue: rust-lang/rust#144361

## Motivation

Currently, it is not possible to use `try_as_dyn` as "specialization-like" dispatch in
blanket impls with `?Sized` type.

```rust
// Cannot add ?Sized now.
impl<T: 'static /* + ?Sized */, S: Serializer + 'static> Serialize<S> for T {
    fn serialize(&self, serializer: &mut S) -> Result<S::Ok, S::Error> {
        if let Some(spec) = try_as_dyn::<_, dyn SpecializedSer<S>>(self) {
            spec.specialized_serialize(serializer)
        } else {
            // fall back to compile-time reflection via TypeId
            ...
        }
    }
}
```

2026-05-05 02:50:12 +02:00

..

src

Rollup merge of #156104 - aobatact:try-as-dyn-unsized, r=oli-obk

2026-05-05 02:50:12 +02:00

Cargo.toml

add autodiff examples

2025-11-16 23:35:37 -05:00