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.
Add Encode/Decode/BorrowDecode constraints for struct generic type parameters in derive macro's outputs #451
Description
For example:
// raw code
use bincode::Encode;
#[derive(Encode)]
struct Foo<T> {
inner: T,
}
// current derive macro output, and it's failed to compile!
use bincode::Encode;
struct Foo<T> {
inner: T,
}
impl<T> bincode::enc::Encode for Foo<T> {
fn encode<E: bincode::enc::Encoder>(
&self,
mut encoder: E,
) -> core::result::Result<(), bincode::error::EncodeError> {
bincode::enc::Encode::encode(&self.inner, &mut encoder)?;
Ok(())
}
}
// what it should ouput
use bincode::Encode;
struct Foo<T> {
inner: T,
}
impl<T: Encode> bincode::enc::Encode for Foo<T> {
fn encode<E: bincode::enc::Encoder>(
&self,
mut encoder: E,
) -> core::result::Result<(), bincode::error::EncodeError> {
bincode::enc::Encode::encode(&self.inner, &mut encoder)?;
Ok(())
}
}The current macro needs the type parameter T be T: Encode. But in Rust, the latter one is more common.
I think most of derive macros in Rust ecosystem like serde::Serialize do the latter way.
So it's better for users when bincode's derive macros do it so.