Free_function = "" causes compilation fail when using an array

[be1]

For some reason, a C library I am using (libmpdclient) does not provide a direct free function for a simple struct, named struct mpd_pair, but a slightly more complex function with a context as parameter.

So, I have to use free_function = "" for the compact class of that C struct in the vapi file, and use another function manually to actually free the struct.

But this makes Vala 0.56.16 generate wrong C code that fails to compile when using an Array of that struct (aka Mpd.Pair[]), at “free” time:

browser_artists = (_vala_array_free (browser_artists, browser_artists_length1, (GDestroyNotify) ), NULL);

Where the (GDestroyNotify) cast is missing an arg (which is the free_function arg, and should be NULL in my case).

The error reported is indeed:

error: expected expression before ‘)’ token

Here is the compact class:

        [CCode (cname = "struct mpd_pair",
                free_function = "")]
        [Compact]
        public class Pair { 
                public unowned string name;
                public unowned string value;
                ...

Is it a valac 0.56 bug to not insert the NULL pointer as GDestroyNotify arg ?

[Sid]

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