BUG #8211: Syntax error when creating index on expression

The following bug has been logged on the website:

Bug reference:      8211
Logged by:          Andrey Cizov
Email address:      acizov@gmail.com
PostgreSQL version: 9.2.3
Operating system:   Windows
Description:        =


CREATE INDEX heuristic ON foos (1 / (a + b))

causes: =


ERROR:  syntax error at or near "1"
LINE 1: CREATE INDEX heuristic ON foos (1 / (a + b))
                                        ^

********** Error **********

ERROR: syntax error at or near "1"
SQL state: 42601
Character: 33

While:

CREATE INDEX heuristic ON foos ((1 / (a + b)))

Execution successful