Should global-actor-isolated functions be implicitly Sendable?

[mattie]

Whipped something up here:

Implicitly Sendable Functions

According to SE-0316: A non-protocol type that is annotated with a global actor implicitly conforms to Sendable . However, this actually isn't true for closures today. @MainActor class MyClass { func doThing() { } } func test() { let closure: @MainActor () -> Void = { print("hmmmm") } let value = MyClass() Task { // warning about capturing non-Sendable await closure() // this is fine await value.doThing() } } A solution is to mark closure as both @MainActor and also @S…