iterator-slot-fences.ts:14:9 - error SC1090: 'Countdown' values in an iterator-typed slot (Iterator and IterableIterator slots hold generators and built-in collection iterators) is not supported yet

  13 | }
  14 | firstOf(new Countdown());
     |         ^~~~~~~~~~~~~~~
  15 | 

iterator-slot-fences.ts:16:16 - error SC2020: 'Iterable<number>' is part of the standard library types but has no scriptc lowering yet

  15 | 
  16 | function total(values: Iterable<number>): number {
     |                ^~~~~~
  17 |   let sum = 0;

  hint: the type checker sees the full standard library, but only the supported surface compiles (https://scriptc.dev/limitations)

iterator-slot-fences.ts:21:13 - error SC2004: uses of 'total' inherit the blocker on its declaration

  20 | }
  21 | console.log(total([1, 2]));
     |             ^~~~~
  22 | 

  hint: the declaration of 'total' did not compile — fix the diagnostic reported there and these sites clear with it