[Bug] Incorrect ssz::Encode implementation

[blombern]

Component

primitives

What version of Alloy are you on?

alloy-primitives v0.5.2

Operating System

macOS (Apple Silicon)

Describe the bug

From ssz_fixed_len method doc: Fixed-length objects must return a value which represents their length. Unless I'm missing something, shouldn't the Encode and Decode traits return the same value?

use alloy_primitives::{FixedBytes, B256};
use ssz::{Decode, Encode};

pub const BLS_PUBLIC_KEY_BYTES_LEN: usize = 48;
pub type BlsPublicKey = FixedBytes<BLS_PUBLIC_KEY_BYTES_LEN>;

fn main() {
    let len_e = <B256 as Encode>::ssz_fixed_len();
    let len_d = <B256 as Decode>::ssz_fixed_len();
    // prints: 4 32
    println!("{} {}", len_e, len_d);

    let len_e = <BlsPublicKey as Encode>::ssz_fixed_len();
    let len_d = <BlsPublicKey as Decode>::ssz_fixed_len();
    // prints: 4 48
    println!("{} {}", len_e, len_d);
}