v/vlib/compiler/tests/defer_test.v

fn foo() string {
	println('foo()')
	return 'foo'
}

fn foo2() string {
	println('start')
	defer { println('defer') }
	defer { println('defer2') }
	println('end')
	return foo()
}

fn test_defer() {
	assert foo2() == 'foo'
}

fn set_num(i int, n mut Num) {
	defer { n.val+=1 }
	println("Hi")
	if i < 5 {
		return
	} else {
		n.val+=1
	}
}

fn set_num_opt(n mut Num) ?int {
	defer { n.val = 1 }
	return 99
}

struct Num {
mut:
	val int
}

fn test_defer_early_exit() {
	mut sum := Num{0}
	for i in 0..10 {
		set_num(i, mut sum)
	}
	println("sum: $sum.val")
	assert sum.val == 15
}

fn test_defer_option() {
	mut ok := Num{0}
	set_num_opt(mut ok)
	assert ok.val == 1
}