xcode uses wrong version of NSManagedObjectContext.perform

Question

I increased the target version, and xcode started giving me an error

Expression is 'async' but is not marked with 'await'" on each usage of NSManagedObjectContext.perform().

let context: NSManagedObjectContext = ... context.perform{...}

It thinks I use newer method

NSManagedObjectContext.perform<T>(schedule::() throws -> T) async rethrows -> T,

but I don't.

How to make xcode to compile with old perform(() -> Void)?

Adding explicit closure header

let context: NSManagedObjectContext = ... context.perform{() -> Void in ...}

is not helpful.

5,8847 gold badges60 silver badges104 bronze badges

Sweeper 294k23 gold badges262 silver badges442 bronze badges · Accepted Answer

Your call must have been in an async context. Apparently in an async context, Swift prioritises resolving to async methods.

You can have it resolve to the non-async method by introducing a synchronous context. For example, you can write a local function like this

func someAsyncFunction() async { func helper() { someContext.perform { ... } } helper() }

More generally, you can write

func run<R>(block: () -> R) -> R { block() } ... func someAsyncFunction() async { run { someContext.perform { ... } } }