This repository was archived by the owner on Aug 15, 2025. It is now read-only.
This repository was archived by the owner on Aug 15, 2025. It is now read-only.
Deriving Decode with nested Cows #431
Description
Hello
Apologies if this isn't the proper medium to ask this. I'm trying something similar to the code below:
use bincode::{de::Decode, enc::Encode, Decode, Encode};
use std::borrow::Cow;
#[derive(Encode, Decode)]
struct T<'a, A: Clone + Encode + Decode> {
t: Cow<'a, U<'a, A>>,
}
#[derive(Clone, Encode, Decode)]
struct U<'a, A: Clone + Encode + Decode> {
u: Cow<'a, A>,
}which gives me the following error:
error[E0277]: the trait bound `U<'a, A>: Decode` is not satisfied
--> src/main.rs:4:18
|
4 | #[derive(Encode, Decode)]
| ^^^^^^ the trait `Decode` is not implemented for `U<'a, A>`
|
= note: required because of the requirements on the impl of `Decode` for `Cow<'_, U<'a, A>>`
= note: required because of the requirements on the impl of `BorrowDecode<'_>` for `Cow<'_, U<'a, A>>`
note: required by a bound in `borrow_decode`
--> /home/andre/.cargo/registry/src/github.com-1ecc6299db9ec823/bincode-2.0.0-alpha.0/src/de/mod.rs:34:25
|
34 | fn borrow_decode<D: BorrowDecoder<'de>>(decoder: D) -> Result<Self, DecodeError>;
| ^^^^^^^^^^^^^^^^^^ required by this bound in `borrow_decode`
= note: this error originates in the derive macro `Decode` (in Nightly builds, run with -Z macro-backtrace for more info)
For more information about this error, try `rustc --explain E0277`.
The code works if one of the Cows is removed. Is it possible to derive(Decode) in the nested case?