when generating thehashCode of an element, we do use the size returned by__iterate. But in case ofOrdered element, the internal representation of the underlying list might contain undefined elements :

Example:

constm=OrderedMap({a:'a',b:'b'}).remove('a')

m.size is 1, the__iterate function will iterate only one time on theb key, but the internal_list element, will have two elements:[undefined, ['b', 'b']]:

Seehttps://runkit.com/jdeniau/immutable-hashcode-using-internal-list-size

I think that we should not use the value returned by__iterate, and use the object size directly.

Fixes#2002