BUG #16013: Unexpected results from bit field query

The following bug has been logged on the website:

Bug reference:      16013
Logged by:          Daryl Waycott
Email address:      daryl.waycott@edgeintelligence.com
PostgreSQL version: 9.6.9
Operating system:   Ubuntu 18.04.2 LTS
Description:

A query using a right bit shift and an equality on a bit field seems to
return incorrect results. See the following snippet:

DROP TABLE IF EXISTS table1;
CREATE TABLE table1(col_bit_10_1 bit(10) NULL);
INSERT INTO table1 VALUES (B'0000000000');
INSERT INTO table1 VALUES (B'0000000001');
select col_bit_10_1>>1 from table1;
select col_bit_10_1 from table1 where col_bit_10_1>>1 = B'0000000000';

Results:

DROP TABLE
CREATE TABLE
INSERT 0 1
INSERT 0 1
  ?column?  
------------
 0000000000
 0000000000
(2 rows)

 col_bit_10_1 
--------------
 0000000000
(1 row)

The second result set should include both rows.