I’m working with Swift and ran into an issue when using the contains(_:) method on an array. The following code works fine:
let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine
But when I try to use the same contains method with the array declared in a separate variable, I get a compile-time error:
let stringArray = ["hello", "world"]
let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error
Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine.
I understand that when comparing an optional value (Optional("hello")) with a non-optional value ("hello"), Swift automatically promotes the non-optional value to an optional (i.e., "hello" becomes Optional("hello")).
🔗 reference
What I don’t understand is why the first code works but the second one doesn’t, even though both cases involve comparing an optional value with a non-optional value. I know that there are different ways to resolve this, like using nil coalescing or optional binding, but what I’m really looking for is a detailed explanation of why this issue occurs at the compile-time level.
Can anyone explain the underlying reason for this behavior?
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I have a macro that converts expression into a string literal, e.g.:
#toString(variable) -> "variable"
#toString(TypeName) -> "TypeName"
#toString(\TypeName.property) -> "property"
In Xcode 16.3 #toString(TypeName) stopped to work, compilation throws 'Expected member name or initializer call after type name' error.
Everything works fine in Xcode 16.2. I tried to compare build settings between 16.2 and 16.3 but haven't noticed differences that may cause this new error.
The following works in both Xcode versions:
#toString(variable) -> "variable"
#toString(\TypeName.property) -> "property"
Seems like Xcode tries to compile code that shouldn't be compiled because of macro expansion.
Does anybody know what new has appeared in 16.3 and, perhaps, how to fix the problem?
I've narrowed down my question after many rabbit holes - how can C++ code open any view in Swift. I can call functions in swift from C++ (works great), but not async or main actor (or actor at all) functions. And if I'm not mistaken all views are actors if not main actors? When calling from C+ I think its necessary that the first view be the main actor?
I've implemented the code from the WWDC23 C++ interop video (Zoe's image picker) where I made a view in a struct, and just want to call it and let the view do the work.
The compiler immediately gives me 'cannot expose main actors to C++'. If I'm not mistaken, doesn't this block the opening of any kind of swift view from C++? Hopefully I'm missing something obvious, which is likely :)
In Zoe's code was his entry point into the program still Swift and not actually C++ app?
Thanks!
Thanks!
Topic:
Programming Languages
SubTopic:
Swift
At least with macOS Sequoia 15.5 and Xcode 16.3:
$ cat test.cc
#include <locale.h>
#include <string.h>
#include <xlocale.h>
int main(void) {
locale_t l = newlocale(LC_ALL_MASK, "el_GR.UTF-8", 0);
strxfrm_l(NULL, "ό", 0, l);
return 0;
}
$ c99 test.c && ./a.out
Assertion failed: (p->val == key), function lookup_substsearch, file collate.c, line 596.
Abort trap: 6
Why doesn’t deinit support async? At the end of a test, I want to wipe data from HealthKit, and it’s delete function is asynchronous.
Is there any way that I can import a Java module for use from Swift?
Topic:
Programming Languages
SubTopic:
Swift
We have an iOS App built in .NET MAUI (Multi-platform App UI).
This is a web view App.
We wish to integrate APP Clips into this App.
But we are unable to do it, due to less available resources online on such implementation.
We do not wish to share code between .NET MAUI App and App clips
We understand it is not possible to add APP Clips without a parent swift/Xcode app.
As an alternative solution we were thinking to Create a new APP in APP Store Connect using XCode/swift and integrate app clips to it.
This parent app when downloaded by users will only redirect users to our MAIN .NET MAUI app to app store connect.
We need to know if such apps will be approved by APPSTORE Connect? Please guide us on this
Also please do let us know if you have any other solution to integrate App clips to a .NET MAUI App
I have an @objC used for notification.
kTag is an Int constant, fieldBeingEdited is an Int variable.
The following code fails at compilation with error: Command CompileSwift failed with a nonzero exit code if I capture self (I edited code, to have minimal case)
@objc func keyboardDone(_ sender : UIButton) {
DispatchQueue.main.async { [self] () -> Void in
switch fieldBeingEdited {
case kTag : break
default : break
}
}
}
If I explicitly use self, it compiles, even with self captured:
@objc func keyboardDone(_ sender : UIButton) {
DispatchQueue.main.async { [self] () -> Void in
switch fieldBeingEdited { // <<-- no need for self here
case self.kTag : break // <<-- self here
default : break
}
}
}
This compiles as well:
@objc func keyboardDone(_ sender : UIButton) {
DispatchQueue.main.async { () -> Void in
switch self.fieldBeingEdited { // <<-- no need for self here
case self.kTag : break // <<-- self here
default : break
}
}
}
Is it a compiler bug or am I missing something ?
I've been testing my open source libraries with Swift 6.2 and the new Default Actor Isolation concurrency build setting set to MainActor (with Complete strict concurrency turned on). My library Destinations uses protocols extensively, often applying conformance to foundational Swift protocols like Hashable and Identifiable. Many of these basic protocols are not flagged as running on the @MainActor in Beta 1, leading to situations like this:
Given this example code:
public protocol Contentable: Identifiable {
var id: UUID { get }
}
final class ContentModel: Contentable {
let id: UUID = UUID()
}
I get the warning:
Multiline
Conformance of 'ContentModel' to protocol 'Contentable' crosses into main actor-isolated code and can cause data races; this is an error in the Swift 6 language mode
The fix it suggests is to put a @MainActor before the Contentable protocol declaration in ContentModel, which seems to be a new attribute configuration in Swift 6.2. This solves the warning, but would create a lot of extra noise across the codebase.
Was it an oversight or a temporary omission that protocols like Hashable and Identifiable do not run on @MainActor by default, or is there some other reason they are excluded? Considering how often protocols in our code may conform to foundational protocols like this, it seems at odds to the MainActor mode of the Default Actor Isolation setting given that it was created to make concurrency easier and less boilerplate to implement.
Hi,
I’m trying to use the new InlineArray type, but noticed that it is unfortunately only available on macOS 26 and not on macOS 15 and others. As this is quite an essential type, I was wondering if this is intended or will this change in later beta’s? Not having it available on older Darwin platforms would severily limit it’s usage in the coming years.
Thanks!
I’ve been struggling with this issue for a long time. When I try to archive my app to submit it to the App Store, I encounter two errors:
Linker command failed with exit code 1 (use -v to see invocation)
Linker command failed with exit code 1 (use -v to see invocation)
Topic:
Programming Languages
SubTopic:
Swift
This is not a question but more of a hint where I was having trouble with. In my SwiftData App I wanted to move from Swift 5 to Swift 6, for that, as recommended, I stayed in Swift 5 language mode and set 'Strict Concurrency Checking' to 'Complete' within my build settings.
It marked all the places where I was using predicates with the following warning:
Type '' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode
I had the same warnings for SortDescriptors.
I spend quite some time searching the web and wrapping my head around how to solve that issue to be able to move to Swift 6. In the end I found this existing issue in the repository of the Swift Language https://github.com/swiftlang/swift/issues/68943. It says that this is not a warning that should be seen by the developer and in fact when turning Swift 6 language mode on those issues are not marked as errors.
So if anyone is encountering this when trying to fix all issues while staying in Swift 5 language mode, ignore those, fix the other issues and turn on Swift 6 language mode and hopefully they are gone.
I want to understand what the recommended way is for string interoperability between swift and c++. Below are the 3 ways to achieve it. Approach 2 is not allowed at work due to restrictions with using std libraries.
Approach 1:
In C++:
char arr[] = "C++ String";
void * cppstring = arr;
std::cout<<"before:"<<(char*)cppstring<<std::endl; // C++ String
// calling swift function and passing the void buffer to it, so that swift can update the buffer content
Module1::SwiftClass:: ReceiveString (cppstring, length);
std::cout<<"after:"<<(char*)cppstring<<std::endl; // SwiftStr
In Swift:
func ReceiveString (pBuffer : UnsafeMutableRawPointer , pSize : UInt ) -> Void
{
// to convert cpp-str to swift-str:
let swiftStr = String (cString: pBuffer.assumingMemoryBound(to: Int8.self));
print("pBuffer content: \(bufferAsString)");
// to modify cpp-str without converting:
let swiftstr:String = "SwiftStr"
_ = swiftstr.withCString { (cString: UnsafePointer<Int8>) in
pBuffer.initializeMemory(as: Int8.self, from: cString, count: swiftstr.count+1)
}
}
Approach 2:
The ‘String’ type returned from a swift function is received as ‘swift::String’ type in cpp. This is implicitly casted to std::string type. The std::string has the method available to convert it to char *.
void
TWCppClass::StringConversion ()
{
// GetSwiftString() is a swift call that returns swift::String which can be received in std::string type
std::string stdstr = Module1::SwiftClass::GetSwiftString ();
char * cstr = stdstr.data ();
const char * conststr= stdstr.c_str ();
}
Approach 3:
The swift::String type that is obtained from a swift function can be received in char * by directly casting the address of the swift::String. We cannot directly receive a swift::String into a char *.
void
TWCppClass::StringConversion ()
{
// GetSwiftString() is a swift call that returns swift::String
swift::String swiftstr = Module1::SwiftClass::GetSwiftString ();
// obtaining the address of swift string and casting it into char *
char * cstr = (char*)&swiftstr;
}
Is anyone have this problem on xcode 26 ?
Undefined symbol: _swift_FORCE_LOAD$_swiftCompatibility50
Undefined symbol: _swift_FORCE_LOAD$_swiftCompatibility51
Undefined symbol: _swift_FORCE_LOAD$_swiftCompatibility56
Undefined symbol: _swift_FORCE_LOAD$_swiftCompatibilityConcurrency
Undefined symbol: _swift_FORCE_LOAD$_swiftCompatibilityDynamicReplacements
Hi, I've got this view model that will do a search using a database of keywords. It worked fine when the SearchEngine wasn't an actor but a regular class and the SearchResult wasn't a Sendable. But when I changed them, it returned Type of expression is ambiguous without a type annotation error at line 21 ( searchTask = Task {). What did I do wrong here? Thanks.
protocol SearchableEngine: Actor {
func searchOrSuggest(from query: String) -> SearchResult?
func setValidTitles(_ validTitles: [String])
}
@MainActor
final class SearchViewModel: ObservableObject {
@Published var showSuggestion: Bool = false
@Published var searchedTitles: [String] = []
@Published var suggestedKeyword: String? = nil
private var searchTask: Task<Void, Never>?
private let searchEngine: SearchableEngine
init(searchEngine: SearchableEngine) {
self.searchEngine = searchEngine
}
func search(_ text: String) {
searchTask?.cancel()
searchTask = Task {
guard !Task.isCancelled else { return }
let searchResult = await searchEngine.searchOrSuggest(from: text) ?? .notFound
guard !Task.isCancelled else { return }
await MainActor.run {
switch searchResult {
case let .searchItems(_, items):
showSuggestion = false
searchedTitles = items.map(\.title)
suggestedKeyword = nil
case let .suggestion(keyword, _, items):
showSuggestion = true
searchedTitles = items.map(\.title)
suggestedKeyword = keyword
case .notFound:
showSuggestion = false
searchedTitles = []
suggestedKeyword = nil
}
}
}
}
}
Hello Everyone! I started programming 6 months ago and started Swift / IOS last month. My learning so far has mainly been with Python. I learned a lot of the package ‘SQLAlchemy’, which has very ‘example based’ documentation. If I wanted to learn how to make a many to many relationship, there was a demonstration with code. But going into Swift and Apple packages, I notice most of the documentation is definitions of structures, modifiers, functions, etc. I wanted to make the equivalent of python ‘date times’ in my swift app. I found the section in the documentation “Foundation->Dates & Times”, but I couldn’t figure how to use that in my code.
I assume my goal should not be to memorize every Swift and apple functionality by memory to be an app developer. So I would appreciate advice on how to approach this aspect of learning programming.
Topic:
Programming Languages
SubTopic:
Swift
When i am trying to archive a framework for ML, using below command:
xcodebuild -workspace "./src/MLProject.xcworkspace" -configuration "Release" -sdk "iphoneos" -archivePath "./gen/out/Archives/Release-iphoneos/MLProject" -scheme "MLProject" -derivedDataPath "./gen/out/" archive BUILD_LIBRARY_FOR_DISTRIBUTION=YES SKIP_INSTALL=NO
The same command used to work fine on Xcode 16.4.
Attached is the detailed error
MLProject_Archive_failure.txt
"the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions" ...... it killing me !!!!
macOS Tahoe ships with Ruby 2.6.10 which was End Of Life in April 2022 (https://www.ruby-lang.org/en/downloads/branches/). How can I either upgrade it to Ruby 3.4.7 or delete it, so that my mac meets minimum cybersecurity requirements?
I use rbenv for more recent versions of Ruby at the moment so don't need any suggestions on how to do add them, I just need rid of the dangerously out of date system Ruby, thanks.
Topic:
Programming Languages
SubTopic:
General
In trying to convert some Objective-C to Swift, I have a subclass of NSWindowController and want to write a convenience initializer. The documentation says
You can also implement an NSWindowController subclass to avoid requiring client code to get the corresponding nib’s filename and pass it to init(windowNibName:) or init(windowNibName:owner:) when instantiating the window controller. The best way to do this is to override windowNibName to return the nib’s filename and instantiate the window controller by passing nil to init(window:).
My attempt to do that looks like this:
class EdgeTab: NSWindowController
{
override var windowNibName: NSNib.Name? { "EdgeTab" }
required init?(coder: NSCoder)
{
super.init(coder: coder)
}
convenience init()
{
self.init( window: nil )
}
}
But I'm getting an error message saying "Incorrect argument label in call (have 'window:', expected 'coder:')". Why the heck is the compiler trying to use init(coder:) instead of init(window:)?