Some questions about the Iter

[guuzaa]

The document says Iter is a type alias for ((T) -> IterResult) -> IterResult. And if we want to use for _ in ... on a type, we must define an Iter function for it. However, I found a problem in the Array (see the photo).

In the implementation, it uses for _ in ... on self, where it refers to the Array. However, we haven't defined any Iter function for it yet. How does it work? Am I mistaken?
If you could help me, I would appreciate it.

[Yoorkin]

The for..in.. loop for arrays will be transformed into an index loop. This is specialized by the compiler. Please do not rely on this behavior, it might be changed.