Cannot use -enable-objc-interop on Linux with Foundation

[gabryon99]

Description

Hello!

We have a Swift class annotated with @obj and we would like to expose its methods to Objective-C. The package is built with SPM using the latest Ubuntu 24.04 toolchain: swift-5.10.1-RELEASE-ubuntu20.04.

However, similarly to what happened in #64457, when the flag -enable-objc-interop is set, Foundation cannot be used. The building process is interrupted by the error explained down below.

Reproduction

1. Download a Swift toolchain for Ubuntu (https://www.swift.org/install/linux/ubuntu/#versions)
2. Create a new Swift package mkdir objc-test && cd objc-test && swift package init.
3. In Package.swift, set the -enable-objc-interop compiler flag:

// swift-tools-version: 5.10
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "objc-test",
    products: [
        .library(
            name: "objc-test",
            targets: ["objc-test"]),
    ],
    targets: [
        .target(
            name: "objc-test",
            swiftSettings: [.unsafeFlags(["-Xfrontend", "-enable-objc-interop"])]),
        .testTarget(
            name: "objc-testTests",
            dependencies: ["objc-test"]),
    ]
)

4. In the Swift file Sources/objc-test/objc_test.swift, write the following example code:

import Foundation

@objc
class Wrapper : NSObject {

    @objc
    static func foo(msg: NSString) -> NSString? {
        return nil
    }
}

5. Run swift build on the terminal, and you will get the following error:

Building for debugging...
error: emit-module command failed with exit code 1 (use -v to see invocation)
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:90:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSArray(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:91:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSData(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:92:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSDate(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:93:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSDictionary(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:94:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSObject(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:95:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSOrderedSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:96:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSNumber(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:97:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:98:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSString(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:99:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSTimeZone(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:100:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSValue(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:101:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSCFConstantString(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:102:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSIndexSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:103:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSAttributedString(NSISARGTYPE arg);
          ^
<unknown>:0: error: could not build Objective-C module 'CoreFoundation'
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:90:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSArray(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:91:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSData(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:92:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSDate(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:93:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSDictionary(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:94:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSObject(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:95:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSOrderedSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:96:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSNumber(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:97:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:98:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSString(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:99:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSTimeZone(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:100:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSValue(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:101:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSCFConstantString(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:102:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSIndexSet(NSISARGTYPE arg);
          ^
<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "CoreFoundation.h"
        ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/CoreFoundation.h:103:
#include <CoreFoundation/ForSwiftFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:10: note: in file included from /home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForSwiftFoundationOnly.h:27:
#include <CoreFoundation/ForFoundationOnly.h>
         ^
/home/gabriele-pappalardo/Downloads/swift-5.10.1-RELEASE-ubuntu24.04/usr/lib/swift/CoreFoundation/ForFoundationOnly.h:103:11: error: unknown type name 'BOOL'
CF_EXPORT BOOL _NSIsNSAttributedString(NSISARGTYPE arg);
          ^
<unknown>:0: error: could not build Objective-C module 'CoreFoundation'
error: fatalError

Expected behavior

Foundation should be usable on Linux when Objective-C interoperability is enabled (i.e., the flag -enable-objc-interop is set).

Environment

• Output of swift --version:

Swift version 5.10.1 (swift-5.10.1-RELEASE)
Target: x86_64-unknown-linux-gnu

• Operating System: Ubuntu 24.04 LTS - Linux 6.8.0-41-generic #41-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 2 20:41:06 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Additional information

No response