make sure structs are expanded until fixpoint #432

Job	Run time
static analysis (Elixir 1.15.x \| Erlang/OTP 26.x)	58s
mix test windows (Elixir 1.12.x \| Erlang/OTP 22.x)	1m 17s
mix test windows (Elixir 1.12.x \| Erlang/OTP 23.x)	1m 30s
mix test (Elixir 1.12.x \| Erlang/OTP 22.x)	58s
mix test windows (Elixir 1.12.x \| Erlang/OTP 24.x)	1m 51s
mix test (Elixir 1.12.x \| Erlang/OTP 23.x)	1m 5s
mix test windows (Elixir 1.13.x \| Erlang/OTP 22.x)	1m 37s
mix test (Elixir 1.12.x \| Erlang/OTP 24.x)	1m 14s
mix test windows (Elixir 1.13.x \| Erlang/OTP 23.x)	1m 35s
mix test (Elixir 1.13.x \| Erlang/OTP 22.x)	1m 4s
mix test windows (Elixir 1.13.x \| Erlang/OTP 24.x)	2m 12s
mix test (Elixir 1.13.x \| Erlang/OTP 23.x)	1m 9s
mix test windows (Elixir 1.13.x \| Erlang/OTP 25.x)	2m 2s
mix test (Elixir 1.13.x \| Erlang/OTP 24.x)	56s
mix test windows (Elixir 1.14.x \| Erlang/OTP 23.x)	1m 35s
mix test (Elixir 1.13.x \| Erlang/OTP 25.x)	43s
mix test windows (Elixir 1.14.x \| Erlang/OTP 24.x)	1m 21s
mix test (Elixir 1.14.x \| Erlang/OTP 23.x)	46s
mix test windows (Elixir 1.14.x \| Erlang/OTP 25.x)	2m 2s
mix test (Elixir 1.14.x \| Erlang/OTP 24.x)	58s
mix test windows (Elixir 1.14.x \| Erlang/OTP 26.x)	2m 37s
mix test (Elixir 1.14.x \| Erlang/OTP 25.x)	40s
mix test windows (Elixir 1.15.x \| Erlang/OTP 24.x)	2m 4s
mix test (Elixir 1.14.x \| Erlang/OTP 26.x)	58s
mix test windows (Elixir 1.15.x \| Erlang/OTP 25.x)	1m 28s
mix test (Elixir 1.15.x \| Erlang/OTP 24.x)	55s
mix test windows (Elixir 1.15.x \| Erlang/OTP 26.x)	1m 18s
mix test (Elixir 1.15.x \| Erlang/OTP 25.x)	58s
mix test (Elixir 1.15.x \| Erlang/OTP 26.x)	1m 6s
	38m 57s

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