autofree compile error: '{' expected (got ";")

[kbkpbot]

Describe the bug

compile a program which re-assignment a mut array, when compile with autofree, it will fail with error: '{' expected (got ";")

Reproduction Steps

a.v

module main

struct MyS {
        a int
}

fn need_free(mut x []MyS) {
        x = []MyS{}
}

fn main() {
        mut xx := []MyS{}

        need_free(mut xx)
}

v a.v -autofree -showcc -keepc

Expected Behavior

compile & run ok

Current Behavior

$ v a.v -autofree -showcc -keepc
> C compiler cmd: '/media/HD/github/lang/v/thirdparty/tcc/tcc.exe' '@/tmp/v_1000/a.tmp.c.rsp'
> C compiler response file "/tmp/v_1000/a.tmp.c.rsp":
  -fwrapv -o "/home/mars/v/bug/autofree/a" "/tmp/v_1000/a.tmp.c" -std=gnu99 -D_DEFAULT_SOURCE -bt25
> C compiler cmd: 'cc' '@/tmp/v_1000/a.tmp.c.rsp'
> C compiler response file "/tmp/v_1000/a.tmp.c.rsp":
  -fwrapv -o '/home/mars/v/bug/autofree/a' "/tmp/v_1000/a.tmp.c" -std=gnu99 -D_DEFAULT_SOURCE
================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/a.tmp.c:5879: error: '{' expected (got ";")
=================================================================
(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 .

Possible Solution

No response

Additional Information/Context

generated C code:

VV_LOC void main__need_free(Array_main__MyS* x) {
        array _sref67 = (x); // free array on re-assignment2
        *x = builtin____new_array_with_default(0, 0, sizeof(main__MyS), 0);
        builtin__array_free(&_sref67);
}

V version

V 0.4.12 8fa8354

Environment details (OS name and version, etc.)

V full version	V 0.4.12 8fa8354
OS	linux, Ubuntu 24.04.3 LTS
Processor	8 cpus, 64bit, little endian, Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
Memory	10.3GB/15.51GB
V executable	/media/HD/github/lang/v/v
V last modified time	2025-09-21 15:13:19
V home dir	OK, value: /media/HD/github/lang/v
VMODULES	OK, value: /home/mars/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/mars/v/bug/autofree
Git version	git version 2.43.0
V git status	0.4.12-9-g8fa8354b
.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 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 696c1d84
emcc version	N/A
glibc version	ldd (Ubuntu GLIBC 2.39-0ubuntu8.5) 2.39

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