BUG #14748: Invalid statement should raise parse error, but ignores invalid part instead

The following bug has been logged on the website:

Bug reference: 14748
Logged by: John Huss
Email address: johnthuss(at)gmail(dot)com
PostgreSQL version: 9.6.1
Operating system: Linux
Description:

This statement is invalid because the 'AND' should be a WHERE or a comma:

update mytable set active = false and foreign_ID = 18984

But when executed it doesn't raise a parse error and simply ignores the
'and' and everything after it.

The result of the statement is that every row in the table is updated with
active=false.

I would expect this to throw a parse error.