A confusing "conflict implementation" when implementing the curves for customized trait.

[ChenxingLi]

I'm trying to implement a trait for a projective curve with the following code

use ark_bls12_381;
use ark_ec::PairingEngine;

pub trait CustomizedTrait {}

impl CustomizedTrait for <ark_bls12_381::Bls12_381 as PairingEngine>::G1Projective {}
impl CustomizedTrait for u64 {}

However, the rust compiler results in an error. It thinks u64 and <Bls12_381 as PairingEngine>::G1Projective are the same type.

error[E0119]: conflicting implementations of trait `CustomizedTrait` for type `u64`:
  --> src\main.rs:31:1
   |
30 | impl CustomizedTrait for <ark_bls12_381::Bls12_381 as PairingEngine>::G1Projective {}
   | ---------------------------------------------------------------------------------- first implementation here
31 | impl CustomizedTrait for u64 {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `u64`

But if I implement the trait for the projective curve directly, every things go well.

use ark_bls12_381;
use ark_ec::PairingEngine;

pub trait CustomizedTrait {}

impl CustomizedTrait for ark_bls12_381::G1Projective {}
impl CustomizedTrait for u64 {}

Have you met this problem when developing such project, especially when implementing the serialization components?

[Pratyush]

I think this is a problem with Rust atm, not our libraries; it might be related to lazy normalization. I’ll try to produce an independent example

[Pratyush]

Is this still an issue with the latest stable?

[ChenxingLi]

Is this still an issue with the latest stable?

Yes, this issue still exists with the most recent rust version 1.64.0 and arkworks version 0.3.0.