Build fails with newer vala

I can not longer compile this projects as it fails with errors like this:

[ 36s] xcb.vapi:4888.17-4888.41: error: Casting of struct Xcb.CharinfoIterator' to Xcb._CharinfoIterator' is not allowed [ 36s] 4888 | if (((_CharinfoIterator)this).rem > 0) [ 36s] | ^~~~~~~~~~~~~~~~~~~~~~~~~
[ 36s] xcb.vapi:4890.39-4890.63: error: Casting of struct Xcb.CharinfoIterator' to Xcb._CharinfoIterator' is not allowed [ 36s] 4890 | unowned Charinfo? d = ((_CharinfoIterator)this).data; [ 36s] | ^~~~~~~~~~~~~~~~~~~~~~~~~
[ 36s] xcb.vapi:5166.17-5166.36: error: Casting of struct Xcb.RgbIterator' to Xcb._RgbIterator' is not allowed [ 36s] 5166 | if (((_RgbIterator)this).rem > 0) [ 36s] | ^~~~~~~~~~~~~~~~~~~~

compile.log.txt

I am now using following setup (using meson or cmake does not make any difference, even using the git head does not work):

Setups:

Library	Works	Does not work
glib	2.62.6	2.72.3
vala	0.48.10	0.56.1
libxcb	1.13	1.15
gtk3	3.24.20	3.24.34
xkb	1.3.0	1.4.1

Edit: I tested using an older vala version and it works same setup ("Does not work") but with vala 0.54.6 works. So this is a vala related issue.