IO.gets/1 slowly expands expressions

[antedeguemon]

Elixir and Erlang/OTP versions

Erlang/OTP 25 [erts-13.0.3] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit:ns]

IEx 1.13.4 (compiled with Erlang/OTP 25)

Operating system

MacOS Monterey 12.6

Current behavior

Hey folks! I am not really sure if this is a bug - since expression expansion may be an undocumented feature for IO.gets/1. Regardless, the expansion still takes way longer than the regular expansion from iex (outside of IO.gets/1).

1. Start fetching a line from stdin using IO.gets("prefix: ")
2. Input some keys and press tab
3. Stdin input will freeze and return the possible expression expansions after some good seconds

Expected behavior

I expected IO.gets/1 to not expand expressions when I press tab.

If expansion is a feature, I think it would be good to have it run as fast as the default expansion in IEX if possible.