BUG #3037: strange behave of CHECK constraint

The following bug has been logged online:

Bug reference: 3037
Logged by: Pavel Stehule
Email address: pavel(dot)stehule(at)hotmail(dot)com
PostgreSQL version: 8.3
Operating system: Linux
Description: strange behave of CHECK constraint
Details:

check constraint is incorect for operator SIMILAR

root=# create table products(
barcode char(13) NOT NULL
check (barcode NOT similar to '%[^0-9]%')
);

root=# insert into products values('22');
ERROR: new row for relation "products" violates check constraint
"products_barcode_check"
root=# insert into products values('aa');
ERROR: new row for relation "products" violates check constraint
"products_barcode_check"

root=# select '22' NOT similar to '%[^0-9]%';
?column?
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t
(1 dka)