BUG #11211: regexp_matches acts like a WHERE

The following bug has been logged on the website:

Bug reference:      11211
Logged by:          Eduard Wulff
Email address:      mail@eduard-wulff.de
PostgreSQL version: 9.4beta2
Operating system:   Debian testing AMD64
Description:

 SELECT vorgangt.id,
  (regexp_matches(vorgangt.text, '#\w{5,26}', 's'))[1] AS sernr,
    regexp_replace(vorgangt.text, '\n', '⁋', 'g') AS text_in_einer_zeile
 FROM vorgangt ORDER BY 1

This works to get the first match if there is one.

BUT: it also _eliminates_ all rows that do not match from the result set

EXPECTED: return NULL or at least an empty string if there is no match