Possible regression: Array passed as optional generic argument

[jorgeluismireles]

This code was from issue #24101 . I was looking for unwrap methods and try the code with current V and failed differently.

V version: V 0.4.12 8342968, press to see full `v doctor` output

V full version	V 0.4.12 c1d1efb.8342968
OS	linux, Ubuntu 22.04.5 LTS
Processor	4 cpus, 64bit, little endian, Intel(R) Core(TM) i3-4150 CPU @ 3.50GHz
Memory	0.42GB/3.7GB
V executable	/home/jorge/v/v
V last modified time	2025-10-14 15:12:48
V home dir	OK, value: /home/jorge/v
VMODULES	OK, value: /home/jorge/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/jorge/bugs
Git version	git version 2.34.1
V git status	weekly.2025.16-904-g83429685-dirty
.git/config present	true
cc version	cc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0
gcc version	gcc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0
clang version	Ubuntu clang version 14.0.0-1ubuntu1.1
tcc version	tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 696c1d84
emcc version	emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.5 ()
glibc version	ldd (Ubuntu GLIBC 2.35-0ubuntu3.11) 2.35

What did you do?
./v -g -o vdbg cmd/v && ./vdbg 251014.v && 251014

fn main() {
	mut arr := []int{}
	mut bbb := unwrap(mut arr)
	bbb << 1
	dump(bbb)
}
fn unwrap[T](mut t ?T) T {
	return t or { panic('unexpected `none`') }
}

What did you see?

================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/251014.01K7HMJ3ED4SZN5CB44QJ467CZ.tmp.c:5228: warning: assignment from incompatible pointer type
cc: /home/jorge/v/thirdparty/tcc/lib/libgc.a: error: 'GC_noop1_ptr' defined twice
cc: tcc: error: undefined symbol 'builtin___option_ok'
...
cc: tcc: error: undefined symbol 'builtin___option_ok'
(note: the original output was 4 lines long; it was truncated to its first 3 lines + the last line)
=================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
builder error: 
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .

What did you expect to see?

compiled program

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[huly-for-github]

Connected to Huly®: V_0.6-26183

[dy-tea]

Works with -no-skip-unused, appears to be a markused regression.