Xcode 10.1 Swift file modification triggers multitude of compiler errors

Question

While editing a Swift file, I am getting several:

@objc attribute used without importing module 'Foundation'
@objc can only be used with members of classes, @objc protocols, and concrete
extensions of classes 
Use of unresolved identifier 
Use of undeclared type

compiler errors.

For instance,

@objc func returnTrue() -> Bool { return true }

complains @objc attribute used without importing module 'Foundation' even though my pch file contains #import <Foundation/Foundation.h>

I have restarted Xcode/Mac; uninstalled/reinstalled Xcode; deleted derived data; changed/reverted the pch file; checked class target memberships; and cleaned the build folder (several times). I can successfully compile and run the code.

Any thoughts?

`@objc func returnTrue() -> Bool { return true }` @LorenzOliveto the compiler is pretty much complaining about everything. — Tom Howard, Jul 03 '19 at 13:25
Why are you using an outdated version of Xcode? 10.2.1 is the latest version. Also, have you tried restarting Xcode? — Dávid Pásztor, Jul 03 '19 at 13:32
@Dávid Pásztor codebase will not compile with latest version (believe it was a swift migration issue); I have restarted Xcode (and my mac). Thanks — Tom Howard, Jul 03 '19 at 13:36
Post the whole relevant code, with a [Minimal, Reproducible Example](https://stackoverflow.com/help/minimal-reproducible-example). — Alejandro Iván, Jul 03 '19 at 13:38
pch file is not available/used in Swift, have you tried adding 'import Foundation' in your Swift class? — LorenzOliveto, Jul 03 '19 at 14:42

score 0 · Answer 1 · answered Jul 05 '19 at 14:16

As a programmer, I am not a fan of magic answers, but the following worked for me (assuming my branch is MyBranch):

Committed and pushed my local MyBranch's working copy changes.
Switched branches. Built. Deleted my local MyBranch.
Checked out the remote MyBranch.

Voila!

Xcode 10.1 Swift file modification triggers multitude of compiler errors

1 Answers1