bincode_derive's Encode and Decode proc macros fail if module declares use anyhow::Ok

[nhaef]

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.

[VictorKoenders]

Looks like in the derive crate, we should replace all Ok instances with core::result::Result::Ok. Test case could be:

fn Ok(){}

#[derive(Encode, Decode)]
struct A { a: u32 }

#[derive(Encode, Decode)]
enum B { A, B }