`PartialOrd` interaction with existing `Ord` impl causes weird error

[lcnr]

The following snippet errors

use std::marker::PhantomData;
use derive_where::derive_where;

trait Interner {}
#[derive_where(PartialOrd, Ord, PartialEq, Eq; I: Interner, T)]
struct Foo<T, I>(T, PhantomData<I>);

with

error[E0277]: the trait bound `T: Ord` is not satisfied
 --> src/main.rs:5:1
  |
5 | #[derive_where(PartialOrd, Ord, PartialEq, Eq; I: Interner, T)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Ord` is not implemented for `T`
  |
note: required for `Foo<T, I>` to implement `Ord`
 --> src/main.rs:5:1
  |
5 | #[derive_where(PartialOrd, Ord, PartialEq, Eq; I: Interner, T)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound introduced in this `derive` macro
6 | struct Foo<T, I>(T, PhantomData<I>);
  |        ^^^^^^^^^
  = note: this error originates in the derive macro `::derive_where::DeriveWhere` (in Nightly builds, run with -Z macro-backtrace for more info)

This is as the PartialOrd impl ends up expanding to

impl<T, I> ::core::cmp::PartialOrd for Foo<T, I>
where
    I: Interner,
    T: ::core::cmp::PartialOrd,
{
    #[inline]
    fn partial_cmp(
        &self,
        __other: &Self,
    ) -> ::core::option::Option<::core::cmp::Ordering> {
        ::core::option::Option::Some(::core::cmp::Ord::cmp(self, __other))
    }
}

This feels surprising to me. It feels generally preferable to always duplicate the equality check in PartialOrd instead 🤔 encountered in https://github.com/rust-lang/rust/pull/150271/changes/4c598a80758e59b3a86f54ade6217cb92285cb16..19521d91a0898af7f256ce6d520d641e98547b21#r2717159656

[lcnr]

The same holds with CLone and Copy. We shouldn't use another trait in the derive if there's a T for which the trait bounds will be added.

use std::marker::PhantomData;
use derive_where::derive_where;

trait Interner {}
#[derive_where(Copy, Clone; I: Interner, T)]
struct Foo<T, I>(T, PhantomData<I>);

results in

error[E0507]: cannot move out of a shared reference
 --> src/main.rs:5:1
  |
5 | #[derive_where(Copy, Clone; I: Interner, T)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ move occurs because value has type `Foo<T, I>`, which does not implement the `Copy` trait
  |
  = note: this error originates in the derive macro `::derive_where::DeriveWhere` (in Nightly builds, run with -Z macro-backtrace for more info)

[daxpedda]

Huh, interesting. But yeah, that is a bug.

PR welcome!

[ModProg]

Released as 1.6.1