# Objective
`EntityHashMap` and `EntityHashSet` iterators do not implement
`EntitySetIterator`.
## Solution
Make them newtypes instead of aliases. The methods that create the
iterators can then produce their own newtypes that carry the `Hasher`
generic and implement `EntitySetIterator`. Functionality remains the
same otherwise.
There are some other small benefits, f.e. the removal of `with_hasher`
associated functions, and the ability to implement more traits
ourselves.
`MainEntityHashMap` and `MainEntityHashSet` are currently left as the
previous type aliases, because supporting general `TrustedEntityBorrow`
hashing is more complex. However, it can also be done.
## Testing
Pre-existing `EntityHashMap` tests.
## Migration Guide
Users of `with_hasher` and `with_capacity_and_hasher` on
`EntityHashMap`/`Set` must now use `new` and `with_capacity`
respectively.
If the non-newtyped versions are required, they can be obtained via
`Deref`, `DerefMut` or `into_inner` calls.
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