void msg_location_destroy (struct msg_location *);
struct msg_location *msg_location_dup (const struct msg_location *);
-void msg_location_merge (struct msg_location *, const struct msg_location *);
+void msg_location_merge (struct msg_location **, const struct msg_location *);
bool msg_location_is_empty (const struct msg_location *);
void msg_location_format (const struct msg_location *, struct string *);