In JCR-SQL2, the standard way to quote an identifier (e.g., selector name, literal name, or literal path) is to use square brackets. (See section 6.7.23 in the JCR 2.0 specification.) However, when a path contains a same-name-sibling index, then the path literal also contains square brackets, and our parser gets confused. So this works:

SELECT * FROM [car:Car] WHERE ISDESCENDANTNODE([car:Car],[/foo/bar])

while this does not work (but should):

SELECT * FROM [car:Car] WHERE ISDESCENDANTNODE([car:Car],[/foo/bar[2]])

Note the confusing use of square brackets.