BUG #4933: ts_rewrite() causes segfault when query with more than one node becomes empty

The following bug has been logged online:

Bug reference:      4933
Logged by:          Aaron Marcuse-Kubitza
Email address:      aaronmk@blackducksoftware.com
PostgreSQL version: 8.3.7
Operating system:   Mac OS X 10.5.7
Description:        ts_rewrite() causes segfault when query with more than
one node becomes empty
Details:

Running

SELECT ts_rewrite('''example'' & ''example'''::tsquery,
'''example'''::tsquery, ''::tsquery)

causes the error "LOG:  server process (PID ...) was terminated by signal
11: Segmentation fault". Any combination of &, |, and () using only
'example' nodes causes the same problem.

However, running

SELECT ts_rewrite('''example'''::tsquery, '''example'''::tsquery,
''::tsquery)

works as expected.