Array in closure not updated

[mike-ward]

Describe the bug

Maybe I'm misunderstanding something here but I think this test should pass.

Reproduction Steps

fn add(s string, cb fn (string)) {
	cb(s)
}

fn test_add() {
	mut lines := []string{}
	add('msg', fn [mut lines] (s string) {
		lines << s
	})
	assert lines == ['msg']
}

Expected Behavior

lines should equal ['msg']

Current Behavior

lines is empty

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.6 65966ae

Environment details (OS name and version, etc.)

V full version: V 0.4.6 8215f21.65966ae
OS: macos, macOS, 14.5, 23F79
Processor: 8 cpus, 64bit, little endian, Apple M2

getwd: /Users/mike/Documents/github/coreutils/src/paste
vexe: /Users/mike/Documents/github/v/v
vexe mtime: 2024-07-10 12:48:46

vroot: OK, value: /Users/mike/Documents/github/v
VMODULES: OK, value: /Users/mike/.vmodules
VTMP: OK, value: /tmp/v_501

Git version: git version 2.45.2
Git vroot status: weekly.2024.27-41-g65966aef
.git/config present: true

CC version: Apple clang version 15.0.0 (clang-1500.3.9.4)
thirdparty/tcc status: thirdparty-macos-arm64 5c1d002f

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[yuyi98]

Inherited variables are copied when the anonymous function is created. This means that if the original variable is modified after the creation of the function, the modification won't be reflected in the function.
If you need the value to be modified outside the function, use a reference.

mut i := 0
mut ref := &i
print_counter := fn [ref] () {
	println(*ref)
}

print_counter() // 0
i = 10
print_counter() // 10

Don't know the usual way to deal with it?