Is it possible to implement custom SwiftUI layouts in Swift 6?

[vanvoorden (Rick van Voorden)]

@wadetregaskis

the @preconcurrency attribute seemingly isn't a viable part of the solution anyway since the Swift 5.10 compiler barfs on it

Types that must be MainActor, but cannot be MainActor due to protocol conformance

Yeah, the recommended way to do this is using MainActor.assumeIsolated. The goal of SE-0423: Dynamic actor isolation enforcement from non-strict-concurrency contexts is to streamline this pattern using @preconcurrency protocol conformances since this pattern is so pervasive and necessary to facilitate an incremental migration for an entire ecosystem of Swift code.

I think the nonisolated workaround (with MainActor.assumeIsolated) should compile from 5.10. I'm using this now and it seems to be ok.

Layout will eventually (I assume) be updated by the SwiftUI team in one of the next betas so that these workarounds are no longer needed.