BUG #16464: Unable to restore database backed up with pg_dump into sql that contains expression based index

The following bug has been logged on the website:

Bug reference:      16464
Logged by:          pg user
Email address:      pguser17354@mailinator.com
PostgreSQL version: 12.3
Operating system:   Centos 6
Description:

Hello,
Restoring from pg_dump fails if you have a table with expression based index
where a stored function calls another function.
Ex. SQL with steps to reproduce: https://pastebin.com/raw/CFgxtwSY

Related to:
https://wiki.postgresql.org/wiki/A_Guide_to_CVE-2018-1058:_Protect_Your_Search_Path

Workaround:
Removing "SELECT pg_catalog.set_config('search_path', '', false);" from the
sql dump.