Beta 10 parser error for CREATE STATISTICS IF NOT EXISTS

I'm not seeing an obvious error in my attempt to use CREATE STATISTICS
IF NOT EXISTS. Given this is new, maybe there is a bug in the parser.

Sample output:
psql (10beta1)
Type "help" for help.

o365logs=# select version();
version

--------------------------------------------------------------------------------
----------------------------
PostgreSQL 10beta1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623
(Red Hat 4.8.5-11), 64-bit
(1 row)

o365logs=# CREATE STATISTICS IF NOT EXISTS logs_corrtest (dependencies) ON record_type, operation FROM logs;
ERROR: syntax error at or near "NOT"
LINE 1: CREATE STATISTICS IF NOT EXISTS logs_corrtest (dependencies)...
^
o365logs=# CREATE STATISTICS logs_corrtest (dependencies) ON record_type, operation FROM logs;
CREATE STATISTICS
o365logs=# DROP STATISTICS IF EXISTS logs_corrtest;
DROP STATISTICS
o365logs=#