BUG #15462: WITH ORDINALITY and CTEs don't work

The following bug has been logged on the website:

Bug reference:      15462
Logged by:          Michael Meyer
Email address:      michael.meyer@pace.de
PostgreSQL version: 11.0
Operating system:   Windows 10
Description:        

CTEs don't play nicely together with 'WITH ORDINALITY':

This is working:

SELECT * FROM generate_series(4,1,-1) WITH ORDINALITY;
WITH a AS (SELECT * FROM generate_series(4,1,-1) )
SELECT * FROM a;

whereas this yields syntax error (42601)

WITH a AS (SELECT * FROM generate_series(4,1,-1) )
SELECT * FROM a WITH ORDINALITY;