1  program test.alpha {
 2      mapping map: u32 => u32;
 3      async transition main() -> (u32, Future) {
 4          let x = 5u32;
 5          let f = async {
 6              map.set(0u32, 42u32);
 7              assert(map.get(0u32) == 42u32);
 8              map.set(1u32, map.get(0u32) + x);
 9              assert(x == 5); // ensure we're using the old value of `x` not the updated one after the async block
10              x = 6; // ensure we're able to update `x` in here
11              assert(x == 6);
12              assert(map.get(1u32) == 42u32 + x - 1);
13          };
14          assert(x == 5); // ensure `x` still has its old value
15          x = 7;
16          assert(x == 7);
17  
18          // Ensures that that the async block is actually executed (including the asserts).
19          // This is technically illegal since `await` is not allowed in a transition. However, for testing purposes, this
20          // seems fine for now. We should improve this when we have better testing infra for the interpreter
21          f.await();
22  
23          assert(x == 7); // x should still have its value update outside the async block
24          return (x, f);
25      }
26  }