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.
bincode_derive's Encode and Decode proc macros fail if module declares use anyhow::Ok #756
Description
Hi, first of all congratulations on the launch of bincode v2, I really like the changes.
During the migration to v2, I noticed the following minor issue, and I suspect that this is not intended behaviour:
use anyhow::Ok;
#[derive(Debug, PartialEq, bincode::Encode, bincode::Decode)]
struct Foo(String);
fn main() {
let val = Foo("Bar".to_string());
let config = bincode::config::standard();
let val_encoded = bincode::encode_to_vec(&val, config).unwrap();
let (val_decoded, _) = bincode::decode_from_slice(&val_encoded, config).unwrap();
assert_eq!(val, val_decoded);
}Observed
Compiling the project fails because the derived Encode and Decode implementations return Ok, which is bound to anyhow::Ok due to the use declaration in L1.
Error
error[E0308]: mismatched types
--> src/main.rs:3:28
|
3 | #[derive(Debug, PartialEq, bincode::Encode, bincode::Decode)]
| ^^^^^^^^^^^^^^^
| |
| expected `Result<(), EncodeError>`, found `Result<(), Error>`
| expected `Result<(), EncodeError>` because of return type
|
= note: expected enum `Result<_, EncodeError>`
found enum `Result<_, anyhow::Error>`
= note: this error originates in the derive macro `bincode::Encode` (in Nightly builds, run with -Z macro-backtrace for more info)
error[E0308]: mismatched types
--> src/main.rs:3:45
|
3 | #[derive(Debug, PartialEq, bincode::Encode, bincode::Decode)]
| ^^^^^^^^^^^^^^^
| |
| expected `Result<Foo, DecodeError>`, found `Result<Foo, Error>`
| expected `Result<Foo, DecodeError>` because of return type
|
= note: expected enum `Result<_, DecodeError>`
found enum `Result<_, anyhow::Error>`
= note: this error originates in the derive macro `bincode::Decode` (in Nightly builds, run with -Z macro-backtrace for more info)
Expected
The project should compile.