It seems that when I build for iOS 14.1, the new linker is not used. I had to switch the project to iOS15+, and then it started linking. EDIT: Nope - once I removed the "-Wl -ld_new" (renamed from -ld_prime) flags to let the Xcode 14 build the project without error, I get "Unknown option: -make_mergeable" error again in Xcode 15 beta 8, suggesting that Xcode 15 for some reason decides to not use the new linker without being forced to :(.

I am not sure if the problem was ever resolved, but it definitely happens on iOS 18 & macOS Sequoia

If this is intentional, it’s a really bad decision, I made my own receipt validation just to get rough semi-realtime sales without waiting :/

This is a slide from Efficiency awaits: Background tasks in SwiftUI from WWDC 2022. It literally uses this code, which crashes with the above error when actually used. Can we get some retraction here?

Can we get a retraction for the whole Efficiency awaits: Background tasks in SwiftUI talk from WWDC 2022 please? I believe it is completely wrong, and the author knows it. it uses the following code, which crashes the app when executed, so clearly the code hasn't been ever run and it leaves this section empty because there seems to be no code that could work there - the only mechanism for handling the background downloads is delegate based! I just wasted two days trying to make the above code work, before arriving here to document this futility. Is this some kind of work in progress code, that was started for iOS 16 and never finished, while the remnants remain in the codebase?

Hello everyone, I wrote a comment under one of the above posts, but as the comments are hidden by default, I add it here: Ah, the dreaded "Efficiency awaits: Background tasks in SwiftUI" talk. I believe part of the features from that talk are still not implemented as of March 2025 (the talk probably describes features Apple hoped to release by WWDC 22, but then scrapped or delayed them). The .backgroundTask(.urlSession(...)) {} call described in the later part of the talk is entirely non-existent, and the presented has a placeholder code inside that callback, as there is no valid code which would compile there. Imo the whole talk should be retracted and replaced with a correct info, as I find traces of many developers spending hours and days trying to implement the described solution that doesn't work. See https://developer.apple.com/forums/thread/726443?answerId=823711022#823711022

Thanks, I filed FB17064989

Swift compiler is dumb for these cases, even 3 years later. Just temporarily change the Group or ForEach into eg. VStack, and you'll see the actual problem's error message.