map_get/2 wrongly computed on BDD with difference

[gldubc]

Elixir and Erlang/OTP versions

Elixir 1.20.0-rc.4 (89e0106) (compiled with Erlang/OTP 28)

Operating system

MacOS

Current behavior

Issue with how map_get is computed when there are negations. Repro:

base = open_map([{domain_key(:atom), term()}])
bad = open_map(a: if_set(negation(integer())))
map = negation(union(negation(base), bad))

assert equal?(map, open_map(a: integer()))

{:ok, type} = map_get(map, atom())
assert equal?(type, term())
# currently returns integer()

{:ok, type} = map_get(map, atom([:a]))
assert equal?(type, term())
# currently errors

Expected behavior

Since map is equivalent to open_map(a: integer()), lookup by atom() should return term(), and lookup by :a should return integer().