autofree: test `return x[0]` (optional)

vlib/v/tests/valgrind/1.strings_and_arrays.v

@@ -353,13 +353,21 @@ fn parse_header0(s string) ?string {
 		return error('missing colon in header')
 	}
 	words := s.split_nth(':', 2)
-	// x := words[0]
-	// return x
+	x := words[0]
+	return x
+}
+
+fn parse_header1(s string) ?string {
+	if !s.contains(':') {
+		return error('missing colon in header')
+	}
+	words := s.split_nth(':', 2)
 	return words[0]
 }
 
 fn advanced_optionals() {
 	s := parse_header0('foo:bar') or { return }
+	s2 := parse_header1('foo:bar') or { return }
 }
 
 fn main() {