Differences between = ANY and IN?

Hello,

My colleague has been working on submitting a patch [1] to the Ruby
Rails framework to address some of the problems discussed in [2].
Regardless of whether that change lands, the change in Rails would be
useful since people will be running Postgres versions without this
patch for a while.

My colleague's patch changes SQL generated from Ruby expressions like
`where(id: [1, 2])` . This is currently translated to roughly `WHERE
id IN (1, 2)` and would be changed to `id = ANY('{1,2}')`.

As far as we know, the expressions are equivalent, but we wanted to
double-check: are there any edge cases to consider here (other than
the pg_stat_statements behavior, of course)?

Thanks,
Maciek

[1]: https://github.com/rails/rails/pull/49388
[2]: https://www.postgresql.org/message-id/flat/20230209172651.cfgrebpyyr72h7fv%40alvherre.pgsql#eef3c77bc28b9922ea6b9660b0221b5d