Test case attached, which tries to implement a subclass of GLib.Volume.

The C compilation fails with the following:

/home/sam/build/src/vala-volume.vala.c: In function ‘test_volume_g_volume_interface_init’:
/home/sam/build/src/vala-volume.vala.c:466:18: warning: assignment from incompatible pointer type [enabled by default]
/home/sam/build/src/vala-volume.vala.c:467:7: error: ‘GVolumeIface’ has no member named ‘mount_fn_finish’
/home/sam/build/src/vala-volume.vala.c:469:15: warning: assignment from incompatible pointer type [enabled by default]
/home/sam/build/src/vala-volume.vala.c:471:30: warning: assignment from incompatible pointer type [enabled by default]
/home/sam/build/src/vala-volume.vala.c: In function ‘main’:
/home/sam/build/src/vala-volume.vala.c:510:2: warning: passing argument 1 of ‘_vala_main’ from incompatible pointer type [enabled by default]
/home/sam/build/src/vala-volume.vala.c:496:6: note: expected ‘const gchar *’ but argument is of type ‘char **’
error: cc exited with status 256
Compilation failed: 1 error(s), 7 warning(s)


This is because the mount() async function in the C vtable has C name mount_fn(), but the compile function is called mount_finish(). Vala is assuming its name to be mount_fn_finish().