Can't have thread type as result, option, or multi-return.

[islonely]

Describe the bug

thread.wait() should be able to return any type a function can return. But results, options, and multi-returns are not allowed types for threads.

Reproduction Steps

struct Foo {
mut:
	tx thread !int
	ty thread ?int
	tz thread (int, int)
}

fn Foo.new() Foo {
	mut foo := Foo{
		tx: spawn x(-1)
		ty: spawn y(-1)
		tz: spawn z(-1)
	}
	return foo
}

fn (mut foo Foo) bar() {
	foo.tx.wait() or {
		// error was returned
		0
	}
	foo.ty.wait() or {
		// none was returned
		0
	}
	a_num, b_num := foo.tz.wait()
}

fn x(x int) !int {
	if x < 0 {
		return error('error')
	}
	return x
}

fn y(y int) ?int {
	if y < 0 {
		return none
	}
	return y
}

fn z(z int) (int, int) {
	return (z, z)
}

fn main() {
	mut foo := Foo.new()
	// do something else with foo while foo
	// continues something() on another thread
	foo.bar()
}

Expected Behavior

Expected code to compile and run.

Current Behavior

Unexpected token error is generated.

C:/Users/imado/Documents/test.v:3:12: error: unexpected token `!`, expecting name
    1 | struct Foo {
    2 | mut:
    3 |     tx thread !int
      |               ^
    4 |     ty thread ?int
    5 |     tz thread (int, int)

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.1 639f128

Environment details (OS name and version, etc.)

V full version: V 0.4.1 639f128
OS: windows, Microsoft Windows 11 Pro v22621 64-bit
Processor: 16 cpus, 64bit, little endian,

getwd: C:\Users\imado\Documents\test
vexe: C:\Users\imado\v\v.exe
vexe mtime: 2023-09-05 17:00:49

vroot: OK, value: C:\Users\imado\v
VMODULES: OK, value: C:\Users\imado.vmodules
VTMP: OK, value: C:\Users\imado\AppData\Local\Temp\v_0

Git version: git version 2.33.1.windows.1
Git vroot status: 0.4.1-10-g639f128c
.git/config present: true

CC version: Error: 'cc' is not recognized as an internal or external command,
operable program or batch file.

thirdparty/tcc status: thirdparty-windows-amd64 e90c2620