Backport below commits from upstream:

    commit adac22bf
    Author: Tom Lane <tgl@sss.pgh.pa.us>
    Date:   Fri Dec 19 05:04:35 2008 +0000

        When we added the ability to have zero-element ARRAY[] constructs by adding an
        explicit cast to show the intended array type, we forgot to teach ruleutils.c
        to print out such constructs properly.  Found by noting bogus output from
        recent changes in polymorphism regression test.

    commit 30137bde6db48a8b8c1ffc736eb239bd7381f04d
    Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
    Date:   Fri Nov 13 19:48:26 2009 +0000

        A better fix for the "ARRAY[...]::domain" problem. The previous patch worked,
        but the transformed ArrayExpr claimed to have a return type of "domain",
        even though the domain constraint was only checked by the enclosing
        CoerceToDomain node. With this fix, the ArrayExpr is correctly labeled with
        the base type of the domain. Per gripe by Tom Lane.

    commit 6b0706ac
    Author: Tom Lane <tgl@sss.pgh.pa.us>
    Date:   Thu Mar 20 21:42:48 2008 +0000

        Arrange for an explicit cast applied to an ARRAY[] constructor to be applied
        directly to all the member expressions, instead of the previous implementation
        where the ARRAY[] constructor would infer a common element type and then we'd
        coerce the finished array after the fact.  This has a number of benefits,
        one being that we can allow an empty ARRAY[] construct so long as its
        element type is specified by such a cast.

Besides, this commit also adds 'location' field in array related
structures, but they are not actived yet. Thanks to Heikki's suggestion.