XCode 13 - Task not found in scope?

Question

Created Oct ’21

Replies 6

Boosts 0

Views 3.9k

Participants 5

Hello, I'm trying to perform simple async tasks wrapped in a Task struct but the compiler always says "error: cannot find 'Task' in scope" using XCode 13 with macOS 12's last beta

Even the simplier playground like this one, fails:

import Foundation

func foo() async -> String {
    await withUnsafeContinuation { continuation in
        DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
            continuation.resume(returning: "Hello")
        }
    }
}

func bar() {
    Task {
        let text = await foo()
        print(text)
    }
}

Results in:

error: MyPlayground.playground:13:5: error: cannot find 'Task' in scope

    Task {

    ^~~~

So... is this normal or am I missing something basic (and stupid)?

Thanks

Boost

Answer 1

OOPer OP

Oct ’21

Thanks for sharing your experience. I could have reproduced the issue on Big Sur 11.6 (iOS Blank playground). (With additional error: cannot find 'withUnsafeContinuation' in scope.) I do not think this is normal and you should better send a bug report to Apple.

0

Answer 2

Claude31 OP

Oct ’21

Do you test this code in playground ?

I tested in playGround with Xcode 13 and it works without problem.

You need to add:

import UIKit

1

Answer 3

OOPer OP

Oct ’21

Thanks to Claude31, I could have explored a little more. Instead of import UIKit, import _Concurrency (in addition to import Foundation) will make it. What is odd is we do not need import _Concurrency in app projects. (You should not use import _Concurrency in actual projects, it may be treated as using a private framework.) And one more odd thing is import _Concurrency can be found when I see the generated header for Foundation by Cmd-clicking the line import Foundation.

0

Answer 4

vbergae OP

Oct ’21

Yes, I've tested in playground and macOS app...

I can confirm that using an iOS playground and importing UIKit, it works. But, why? The symbol is part of the Swift Standard Library, why I need to import UIKit? In this way it's impossible to use inside mac apps.

0

Answer 5

Bartosch OP

Oct ’21

I have the same issue in Swift Package

0

Answer 6

Biblbroks OP

Jan ’22

try this

import _Concurrency

1