Someone else must have received this message while (or after) converting an iOS project to Swift 3, yet when I do a Google search, I get no relevant results.
Anyway, after converting to Swift 3, I have about 30 warnings that say:
Expression implicitly coerced from 'UIView?' to Any
But the warnings do not point to any specific line of code. They only reference the class where the warning exists.
Does anyone have an insight into this warning or how I might go about silencing them?
In my case it was an issue related to a dictionary without explicit type:
let dict = ["key": value]
Than I solved specifying the type:
let dict: [String: Any] = ["key": value]
In your case you can specify your value type:
let dict: [String: UIView] = ["key": value]
This will happen when the function you are calling has a parameter of type Any, and you are passing an optional.
For example:
let color: UIColor? = UIColor.red
UIBarButtonItem.appearance().setTitleTextAttributes([NSFontAttributeName: color], for: .normal)
Notice that color is of type UIColor? and that setTitleTextAttributes expects a dictionary of type [String: Any]?.
In order to avoid the warning you have to either force unwrap your optional, or cast it to Any.
UIBarButtonItem.appearance().setTitleTextAttributes([NSFontAttributeName: color!], for: .normal)
or
UIBarButtonItem.appearance().setTitleTextAttributes([NSFontAttributeName: color as Any], for: .normal)
Looks like a bug in the Swift compiler:
https://bugs.swift.org/browse/SR-2921
Currently, I'm seeing this with Xcode 8.1 and 8.2 beta 1.
In your case, the warning should identify the source file, but not the line - as you stated. You will have to hunt around for calls to functions with Any parameters.
Good new is that it appears fixed in an upcoming Swift toolchain.
I believe this is fixed in Xcode 8.3 beta 1 (but have not confirmed)
Problem
The expected type is Any but the type provided was UIView?
The problem is with the optional, just make sure an instance of UIView is passed and things would work.
Related
I have the below line of code in a cocoa pod which I am compiling in Swift 4.1 on Xcode.
let foregroundColor = attributedTitle(for: .normal)?.attribute(.foregroundColor, at: 0, effectiveRange: nil) as? UIColor
The error I am getting for the line is:
Type 'String' has no member 'foregroundColor'
There is a similar discussion here Getting an error: Type 'String' has no member 'foregroundColor' in Swift 4 but what confuses me is that this answer suggests the error I am seeing is in fact one to do with Swift 3.X whereas I am compiling in Swift 4.1.
Also, when I try to edit the line it is blocked (as it is from a cocoa pod) which makes me wonder if there isn't another way of soling it (as messing with the pods will cause a problem every time I update in the future)?
i hope attributedTitle(for: .normal) is a fuction who return a String value, but your code is prepared to recive an attributedString like this:
let attributeTitle = NSAttributedString(string: "StringExample")
let color = attributeTitle.attribute(.foregroundColor, at: 0, effectiveRange: nil) as? UIColor
the problem i hope is the function attributedTitle, search him in the pod and try tu change the return value or check if an update in the library is uploaded.
Swift 2.2 has broken almost all my code. Even this simple string assigning to label doesn't work anymore:
cell.categoryName.text = peopleArray![indexPath.row]["Name"] as? String
The error says "Downcast from 'String?!' to 'String' only unwraps optionals, did you mean to use '!!'?"
What changes do I have to do now.
EDIT:
More Problems:
if (dict["data"]!["DataDetails"] as! NSArray).count == 0 {
}
Due to this I am getting a segmentation fault and the error shows this: warning: cast from 'String?!' to unrelated type 'NSArray' always fails
UPDATE:
I was using NSDictionaries, NSArrays in my classes that seems to cause the problem. Changing all the literals from Obj-C to swift made the code work properly.
So, I will also recommend other developers to prefer swift literals.
it seems there are some slight differences when using the swift types and the objective-c NS... types
eg
let dic:NSDictionary? = ["a":"a"]
let str:NSString? = dic!["a"] as? NSString
let dic2:Dictionary? = ["b":"b"]
let str2:String? = dic2!["b"] //dont need to do any casting, already optional
print(str)
print(str2)
prints
Optional(a)
Optional("b")
so depending on how your array / dictionary is defined, you might need different casting/unwrapping
Hello StackOverflow :)
I've been running into a weird problem since I upgraded to swift 2.0
I'm trying to set a border color, so I'm writing self.layer.borderColor = borderColor as! CGColor where borderColor is an AnyObject, while self.layer.borderColor is a CGColor?
If I write self.layer.borderColor = borderColor as! CGColor I get the warning
Treating a forced downcast to 'CGColor' as optional will never produce 'nil'
and is recommended to instead use as?
If I instead write self.layer.borderColor = borderColor as? CGColor I get the error
Conditional downcast to CoreFoundation type 'CGColor' will always succeed
Just to make sure I wasn't missing something I also tried writing container.layer.borderColor = borderColor as CGColor and container.layer.borderColor = borderColorBoth of these gave the following error:
'AnyObject' is not convertible to 'CGColor'; did you mean to use 'as!' to force downcast?
Just running with the warning given by XCode when using as! is not all that terrible, but I would prefer to keep my code warning free. To avhieve that I really need your help SO. Is this something I'm not understanding or is it simply a bug in Swift 2.0 that I should instead report.
Cheers!
Jacob
You are using layer color, which is core graphics, you need to set core graphic color with property cgColor
layer.borderColor = UIColor.red.cgColor
xcode also gives me the following hint:
Add parentheses around the cast to silence this warning
well... when xcode says so...
layer.borderColor = (borderColor as! CGColor)
Yes, it is a well-know bug and it is still unresolved! Unnecessary message for non-optional to non-optional cast
If you don't like the warning you should follow the Xcode advice:
Add parentheses around the cast to silence this warning.
I know have many the same question but still cannot find the way to fix my error. Please see the image for more detail. I used Xcode 7 and swift 2.0
Edit: fcking the warning of Swift. finnaly (change?[NSKeyValueChangeNewKey]?.boolValue)! fixed the error
change is an optional. Either unwrap the optional
let isCaptureStillImage = change![NSKeyValueChangeNewKey]!.boolValue
or use optional bindings
if let changeNewKey = change?[NSKeyValueChangeNewKey] {
let isCaptureStillImage = changeNewKey.boolValue
...
After updating the xcode and my device some functions are not running anymore.
see It:
var jsonUnico: NSMutableArray! = jsonResult["lista"] as? NSMutableArray
self.tableList.addObjectsFromArray(jsonUnico)
Error: Cannot invoke 'addObjectsFromArray' with an argument list of type '(NSMutableArray!)'
It was working yesterday before upgrading
note: the tablelist is an NSMutableArray
Swift 1.2 no longer implicitly converts between NSArray and Swift’s native array type – you need to explicitly cast from one to the other. Since addObjectsFromArray takes a Swift array, that means you need to convert it to [AnyObject].
Normally you’d get a more helpful error message: error: 'NSMutableArray' is not implicitly convertible to '[AnyObject]'; did you mean to use 'as' to explicitly convert?, with a offer to “fix-it”. But it looks like this isn’t happening because of your use of implicitly-unwrapped optional NSMutableArray!.
But… this isn’t such a bad thing, since using implicitly-unwrapped optionals like that when fetching values out of dictionaries is dangerous (if the entry is ever not there, your app will crash). An alternative is:
if let jsonUnico = jsonResult["lista"] as? NSMutableArray {
let tableList = NSMutableArray()
// Xcode will recommend adding the "as [AnyObject]"
tableList.addObjectsFromArray(jsonUnico as [AnyObject])
}
But since you’re already doing an as above it, you may as well combine them:
if let jsonUnico = jsonResult["lista"] as? [AnyObject] {
tableList.addObjectsFromArray(jsonUnico)
}