Status check: Typed throws

[dmt (Dima Galimzianov)]

This is exactly what I wanted to propose today.
One thing I'd like to add is that it will require some additional logic to be implemented for for [try] await x in y. For context take a look at my workaround for "opaque AsyncSequence"

Type erasure of AsyncSequences

I think I found a workaround, but kinda wordy // Basic trick protocol AsyncThrowingIteratorProtocol<Element>: AsyncIteratorProtocol {} protocol AsyncNonThrowingIteratorProtocol<Element>: AsyncIteratorProtocol { mutating func next() async -> Element? } protocol AsyncSequenceOf<Element>: AsyncSequence {} protocol AsyncNonThrowingSequenceOf<Element>: AsyncSequenceOf where Self.AsyncIterator: AsyncNonThrowingIteratorProtocol {} typealias AsyncStreamAsyncIterator<T> = AsyncStream<T>.AsyncItera…