BUG #15606: Postgres incorrectly returns syntax error when using WITH clacuse

The following bug has been logged on the website:

Bug reference: 15606
Logged by: Rikke Hammer
Email address: newsx(at)outlook(dot)com
PostgreSQL version: 11.1
Operating system: Windows 10 Home version1803 x64
Description:

I get a syntax error when I try to use a WITH clause in a query. Below is a
simple test query. It (as as well as any other WITH clause query I do,
creates the following error:

SQL Error [42601]: ERROR: syntax error at end of input
Position: 53
ERROR: syntax error at end of input
Position: 53
ERROR: syntax error at end of input
Position: 53

CREATE TABLE employees (
employee_id serial PRIMARY KEY,
full_name VARCHAR NOT NULL,
manager_id INT
);

INSERT INTO employees (
employee_id,
full_name,
manager_id
)
VALUES
(1, 'Michael North', NULL),
(2, 'Megan Berry', 1),
(3, 'Sarah Berry', 1),
(4, 'Zoe Black', 1),
(5, 'Tim James', 1),
(6, 'Bella Tucker', 2),
(7, 'Ryan Metcalfe', 2);

WITH emp AS (
select * from rikke_hammer.employees)