Comment by Ben A (JIRA)

Call sites that I can pick out easily that might trigger this seem to be:

• dictionary literals where values are being coerced

• dictionary subscripts where the values are being coerced

But as I said, I've tried explicitly unwrapping values in these cases to no avail.

@rudkx, CodaFi (JIRA User), can you think of where this would happen?

I saw a report of this yesterday, and in that case the issue was a dictionary [ String : UIColor? ] that was being passed to a function expecting [ String : Any ].

I'm not sure why the source location is wrong in that case.

Comment by Ben A (JIRA)

If any headway is made here, I'm happy to try out a snapshot or build a toolchain locally to try it out in Xcode to verify the fix. And of course I'll update here if I can come up with an isolated repro case.

I just figured out what the issue is (at least with the test case I mentioned) and will submit a patch soon.

PR that fixes the source locations: #5259

I opened SR-2928 to track fixing the warning messages and fixits.

Merged: 623a163

The source locations should now appear. Please re-open, or open a new ticket, if you find that it's not happening once you pick up a build that has the fix.

Comment by Ben A (JIRA)

@rudkx thanks!

Comment by Ben A (JIRA)

Tested with swift-DEVELOPMENT-SNAPSHOT-2016-10-13-a, and this is fixed now. Thanks!

Not fixed for me using swift-DEVELOPMENT-SNAPSHOT-2016-11-01 (a)

@dmcgloin Do you have a test case that demonstrates the issue you're seeing?

I will try to extract a simple example as soon as possible

Comment by Mitchell Clay (JIRA)

Noticed this error in XCode 8.1 release, sample code:

func nullToNil(value : Any?) -> Any? {
        if value is NSNull {
            return nil
        }
        return value
}

func parse(json: [String: Any]) {
    let childObject = json["child"] as! [String: Any?]
    let desc = nullToNil(childObject["description"]) as? String
}

I will get "Expression implicitly coerced from Any? to Any" on the "let desc" line

EDIT:

I have realized that this may not be a bug with current version more that it was a bug with previous version that is now fixed. The correct code is:

func nullToNil(value : Any?) -> Any? {
        if value is NSNull {
            return nil
        }
        return value
}

func parse(json: [String: Any]) {
    let childObject = json["child"] as! [String: *Any*]
    let desc = nullToNil(childObject["description"]) as? String
}

Because childObject["description"] is automatically considering the fact that the key may be wrong so a nil value could be returned, but for parsing JSON it will be a value or NSNull.

Here's a snippet that produces a warning without source location.

This occurs with Xcode 8 version 8.1 (8B62) with default Swift 3.
It also occurs with Xcode 8 version 8.1 (8B62) with swift-DEVELOPMENT-SNAPSHOT-2016-10-13-a toolchain.

Please disregard the two warnings about using let instead of var.

    func doTest()
    {
        var color: String? = "Blue"
        var flavor: String? = "Vanilla"
        
        let additionalProperties = ["Color": color, "Flavor": flavor]
        self.logEvent("Something happened", additionalProperties: additionalProperties)
    }

    func logEvent(_ eventName: String, additionalProperties: [String: Any]? = nil)
    {
    }

Comment by Tal (JIRA)

does this appear to be caused by this bug. See attachment.

let message = messageFactory.message(meetHereType: meetHereType, image: image, conversation: conversation, meetLocation: meetLocation, senderLocation: senderLocation, receiverLocation: receiverLocation)
conversation.insert(message) { (error) in
print(error)
}
dismiss()

Comment by Benjamin Encz (JIRA)

Still happening for me in Xcode 8.1 (8B62).

One example:

        let string = NSMutableAttributedString(string: text)
        let linkAttributes =  [NSForegroundColorAttributeName: UIColor.plangridBlue()]
        string.setAttributes(linkAttributes, range: buttonRange)}

Happens in 5 different locations in our codebase.

+1, on Xcode Version 8.2 (8C30a)

Very similar to @dmcgloin's issue–I'm seeing this happen with NSLayout.constraints(withVisualFormat:options:metrics:views:), which expects a [String: Any], when I'm passing in a [String: UITextView?].

Can someone who is hitting this try with a recent snapshot?

It appears to be fixed on master, e.g. for @dmcgloin's example I get:

  7:63: warning: expression implicitly coerced from 'String?' to Any
    self.logEvent("Something happened", additionalProperties: additionalProperties)

I'm still getting this with the 3.0.2 PREVIEW 1 toolchain. Is there anything newer than this that I should try?

Yes, the December 9 snapshot here:

https://swift.org/download/#snapshots

No luck with the 12/9 Snapshot 🙁

[EDIT]: Cleaned the project and tried again, and it's reporting the correct location now.

Comment by Danut Pralea (JIRA)

I keep having the warning, along with no location information 🙁

It's fixed in Swift 3.1 (Xcode 8.3). Any 3.0.x releases still have the bug.