Compiler error when using iter_combinations with filtered query

[rparrett]

Bevy version

0.6
main

What you did

use bevy::prelude::*;

#[derive(Component)]
struct A;
#[derive(Component)]
struct B;

fn test(query: Query<&A, With<B>>) {
    for _ in query.iter_combinations() {}
}

fn main() {}

What actually happened

error[E0277]: the trait bound `WithFetch<B>: Clone` is not satisfied
   --> src/main.rs:8:14
    |
8   |     for _ in query.iter_combinations() {}
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `WithFetch<B>`
    |
    = note: required because of the requirements on the impl of `Iterator` for `QueryCombinationIter<'_, '_, &A, ReadFetch<A>, bevy::prelude::With<B>, {_: usize}>`
    = note: required because of the requirements on the impl of `IntoIterator` for `QueryCombinationIter<'_, '_, &A, ReadFetch<A>, bevy::prelude::With<B>, {_: usize}>`
note: required by `into_iter`
   --> /Users/me/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/collect.rs:234:5
    |
234 |     fn into_iter(self) -> Self::IntoIter;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

What you expected to happen

No compiler error.

Or if this is a known limitation or intended or something special needs to be done to make this work, some documentation pointing that out.

[alice-i-cecile]

This is just a bug, rather than a known limitation. I suspect that just adding the appropriate Clone derives on all the filters + adding some tests will be enough to fix this.

[rparrett]

Yep, seems like adding a Clone impl (deriving doesn't seem to work here?) to WithFetch at least makes things compile.

If nobody else gets to this in the next couple weeks I'll pick it up.