Vec<T> implements PartialEq<[T; N]> but the other way round doesn't work

Hello,

it seems that there is an oversight (or possibly it's wanted behaviour, but it felt odd to me) in how vectors and arrays can be compared, based on PartialEq implementation.

I tried this code:

fn main() {
    let a = vec![1, 2, 3];
    let b = [1, 2, 3];
    
    assert_eq!(a, b);
    assert_eq!(b, a);
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=3c95d140909d5ac62d769b8f663bcd47

I expected to see this happen: No errors because assert_eq should consider these two equal (or shouldn't it?)

Instead, this happened:

   Compiling playground v0.0.1 (/playground)
error[E0277]: can't compare `[{integer}; 3]` with `Vec<{integer}>`
 --> src/main.rs:6:5
  |
6 |     assert_eq!(b, a);
  |     ^^^^^^^^^^^^^^^^ no implementation for `[{integer}; 3] == Vec<{integer}>`
  |
  = help: the trait `PartialEq<Vec<{integer}>>` is not implemented for `[{integer}; 3]`
  = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider dereferencing here
 --> /playground/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/macros/mod.rs:40:35
  |
40|                 if !(*left_val == **right_val) {
  |                                   +

For more information about this error, try `rustc --explain E0277`.
error: could not compile `playground` (bin "playground") due to 1 previous error

Meta

I also checked beta and nightly (on the playground, not on my own machine; please tell me if I should repeat it here), and the results are the same over all three of these.

rustc --version --verbose:

rustc 1.77.2 (25ef9e3d8 2024-04-09)
binary: rustc
commit-hash: 25ef9e3d85d934b27d9dada2f9dd52b1dc63bb04
commit-date: 2024-04-09
host: x86_64-unknown-linux-gnu
release: 1.77.2
LLVM version: 17.0.6

Start with the src/main.rs reproducer and verify the asymmetric comparisons on the relevant Rust toolchain. Then inspect the standard library's PartialEq implementations for Vec and arrays; done means deciding the intended behavior and adding or updating coverage for both comparison directions.