SQL Server doesn't allow to create filtered indexes or indexes on computed columns in temp tables with ansi warnings turned off. Here's a simple example:

set ansi_warnings off

create table #temp ( id int )

create index ix_#temp_id on #temp ( id ) where ( id = 0 )

It boggles my mind why SQL Server has this restriction, especially because I can wrap the create table and index around setting of ansi warnings on and off without errors.

set ansi_warnings on

create table #temp ( id int )

create index ix_#temp_id on #temp ( id ) where ( id = 0 )

set ansi_warnings off