Using Without in Or filters is unsound

[infmagic2047]

Bevy version

Current main (but should also happen with 0.7 release)

What you did

use bevy::prelude::*;

#[derive(Component, Debug)]
struct Foo(u32);

#[derive(Component, Debug)]
struct Bar(u32);

fn setup(mut commands: Commands) {
    commands.spawn().insert(Foo(1));
}

fn test(
    mut query_1: Query<&mut Foo, Or<(Without<Foo>, Without<Bar>)>>,
    mut query_2: Query<&mut Foo, Without<Bar>>,
) {
    let mut x = query_1.single_mut();
    let mut y = query_2.single_mut();
    x.0 = 1;
    println!("{:?} {:?}", *x, *y);
    y.0 = 2;
    println!("{:?} {:?}", *x, *y);
}

fn main() {
    App::new()
        .add_plugins(MinimalPlugins)
        .add_startup_system(setup)
        .add_system(test)
        .run();
}

What you expected to happen

test should be disallowed as it has conflicting queries.

What actually happened

The code runs successfully and prints Foo(1) Foo(1) and Foo(2) Foo(2) repeatedly.

Additional information

Current Or<Without<A>, Without<B>> get recorded as access.add_without(A); access.add_without(B);, which is the cause of problems here. It is probably too difficult to express the "or" condition precisely (filters can encode arbitrary boolean expressions), and a good solution is to handle such a case as if no filters are given.

[alice-i-cecile]

Thanks for spotting this, and the fantastic issue writeup.