C error when outer struct is not locked

[WoodyAtHome]

V doctor:

OS: linux, Ubuntu 20.04.4 LTS
Processor: 4 cpus, 64bit, little endian, Intel(R) Core(TM) i5-3320M CPU @ 2.60GHz
CC version: cc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0

getwd: /home/woody/sources/v/bugs
vmodules: /home/woody/.vmodules
vroot: /home/woody/sources/v/v
vexe: /home/woody/sources/v/v/v
vexe mtime: 2022-07-27 08:53:53
is vroot writable: true
is vmodules writable: true
V full version: V 0.3.0 9ec8a99.6a7eb82

Git version: git version 2.25.1
Git vroot status: weekly.2022.30-10-g6a7eb82d
.git/config present: true
thirdparty/tcc status: thirdparty-linux-amd64 827f7452

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

module main 

import time

struct Alarms {
	mut:
	times shared []time.Time
}

fn (shared alarms Alarms) add(alarm time.Time) {
	lock alarms.times {
		if alarms.times.any(it == alarm) {
			return
		}
		alarms.times << alarm
	}
}

fn main() {
	shared alarms := Alarms{
		times: []time.Time{cap: 10}
	}

	utc := time.utc()
	alarms.add(utc)
}

What did you expect to see?

a compile error in line 11, because alarms is not locked

What did you see instead?

==================
/tmp/v_1000/shared.2802438240981746509.tmp.c:16983: error: struct or union expected
...
==================
(Use `v -cg` to print the entire error message)

builder error: 
==================
C error. This should never happen.

This is a compiler bug, please report it using `v bug file.v`.

https://github.com/vlang/v/issues/new/choose

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