1  program test.alpha {
 2      struct Bar { x: u8? }
 3      struct Foo { b: Bar }
 4  
 5      transition foo(x: u8?, y: [u8?; 3], f: Foo) -> (u8?, u8?, Foo) {
 6          return (x, x, f);
 7      }
 8  
 9      async transition bar(x: u8?, f: Foo) {
10          return async {};
11      }
12  
13      function baz(x: u8?) -> u8? {
14          return x;
15      }
16  }