Private type should not be public

[kbkpbot]

Describe the bug

Private type declare in other module, should not be public.

Reproduction Steps

append a line to vlib/builtin/cfns_wrapper.c.v

type MyPrivateType = u32

then create a file , such as :
p.v

fn main() {
        _ := MyPrivateType(0)
}

then compile it :

v p.v

Expected Behavior

The compiler should issue a error message "error: type MyPrivateType is private"

Current Behavior

compile pass

Possible Solution

No response

Additional Information/Context

Private const/function in builtin mod work OK, they are private to other modules.

V version

V 0.4.9 1b9f15d.5dd28cf

Environment details (OS name and version, etc.)

V full version	V 0.4.9 1b9f15d.5dd28cf
OS	linux, Ubuntu 24.04.1 LTS
Processor	8 cpus, 64bit, little endian, Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
Memory	2.34GB/15.51GB
V executable	/media/HD/github/kbkpbot/v/v
V last modified time	2025-01-19 01:56:59
V home dir	OK, value: /media/HD/github/kbkpbot/v
VMODULES	OK, value: /home/mars/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/mars/v/sort
Git version	git version 2.43.0
V git status	weekly.2025.1-74-g5dd28cf9-dirty (5 commit(s) behind V master)
.git/config present	true
cc version	cc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
gcc version	gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
clang version	Ubuntu clang version 18.1.3 (1ubuntu1)
tcc version	tcc version 0.9.28rc 2024-07-31 HEAD@1cee0908 (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 0134e9b9
emcc version	N/A
glibc version	ldd (Ubuntu GLIBC 2.39-0ubuntu8.3) 2.39

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[huly-for-github]

Connected to Huly®: V_0.6-21947

[kbkpbot]

This bug is related to issue #23453