[Vala] [BUG] Cannot store delegate in a class.

[Jan Hudec <bulb ucw cz>]

Hello folks,

Until recently, I could store a delegate in a class. It was incorrect in many
cases because a destroy notify was not stored in the delegates.

Now the destroy notify is stored, but for some reason fails to be stored in
a class. What is worse, vala does not report any error and silently generates
invalid code:

Case 1:

    delegate bool Predicate();

    class Checker {
        private Predicate predicate;

        public Checker(Predicate predicate) {
            this.predicate = predicate;
        }
    }

    int main(string[] argv) {
        bool result = true;
        var checker = new Checker(() => result);
        return 0;
    }

This compiled in 0.7.5 (though without the destroy notify it was not really
correct), but now it produces invalid code. This particualr snippet gives:

    /tmp/test1.vala.c: In function ‘checker_construct’:
    /tmp/test1.vala.c:77: error: ‘predicate_target_destroy_notify’ undeclared (first use in this function)
    /tmp/test1.vala.c:77: error: (Each undeclared identifier is reported only once
    /tmp/test1.vala.c:77: error: for each function it appears in.)
    error: cc exited with status 256
    Compilation failed: 1 error(s), 1 warning(s)

(and a warning that checker is unused, which is correct)
Expected result:

    Either working code, or vala error that delegate cannot be copied.

Case 2:

    delegate bool Predicate();

    class Checker {
        private Predicate predicate;

        public Checker(owned Predicate predicate) {
            this.predicate = predicate;
        }
    }

    int main(string[] argv) {
        bool result = true;
        var checker = new Checker(() => result);
        return 0;
    }

Since the destroy_notify is defined for owned delegates, I tried making the
constructor parameter owned. It however produces the following error:

    /tmp/test2.vala.c: In function ‘checker_construct’:
    /tmp/test2.vala.c:77: error: lvalue required as left operand of assignment
    /tmp/test2.vala.c: In function ‘_main’:
    /tmp/test2.vala.c:261: warning: passing argument 3 of ‘checker_new’ from incompatible pointer type
    error: cc exited with status 256
    Compilation failed: 1 error(s), 1 warning(s)

(and a warning that checker is unused, which is correct)
Expected result:

    Working code.

I also tried declaring the member 'owned', but that gave me a syntax error
from vala (because it should be owned by default, shouldn't it?)

It might be the same problem as
https://bugzilla.gnome.org/show_bug.cgi?id=592769. It was reported some time
ago while I am quite confident the Case 1 above still compiled yesterday, but
it might be that the recent changes to owned delegate handling just expanded
scope of the existing problem.

-- 
                                                 Jan 'Bulb' Hudec <bulb ucw cz>