`EntityHashSet` can't be used as a relationship target collection because it doesn't implement `VisitEntitiesMut`

[Brezak]

Bevy version

Main branch 3b9e2e6

What you did

• Tried to implement RelationshipSourceCollection for EntityIndexMap.
• Encountered error.
• Attempted to use EntityHashSet to double check.
• Same error.

What went wrong

The Component derive macro implements visit_entities_mut by using VisitEntitiesMut. EntityHashSet and friends can't implement VisitEntitiesMut since mutable access to it's keys could break internal invariants.

[jonmorton]

The proposed fix has been closed, is this issue still blocking milestone 0.16?

[Brezak]

The proposed fix has been closed, is this issue still blocking milestone 0.16?

What proposed fix? If you mean #18260, that mention wasn't in relation to fixing this.

[alice-i-cecile]

Is this still true after #18432 ?

[Brezak]

Is this still true after #18432 ?

EntityHashSet doesn't implement MapEntities so it still won't work. See #18432 (comment) on the reason why.

[alice-i-cecile]

Sounds good. I'm going to clear the milestone then.