error: cannot convert value of type 'T.IndexDistance' to expected argument type 'Int'

[pohetsn]

I've encountered the following error message when building Surge with Carthage. My environment is Xcode 9.2, and I have github "mattt/Surge" ~> 2.1.0 in the Cartfile. Not sure where the T.IndexDistance comes from. Thanks for the help

<project path>/Carthage/Checkouts/Surge/Sources/Surge/Matrix.swift:41:34: error: cannot convert value of type 'T.IndexDistance' to expected argument type 'Int'
        self.init(rows: contents.count, columns: contents.first!.count, repeatedValue: 0.0)
                        ~~~~~~~~~^~~~~
                        Int(          )

[mattt]

IIRC, Swift 4 changed the semantics for collection index distances such that they're now Int, whereas before they were a generic IndexDistance type. Can you please confirm that your project is compiling with Swift 4 and not Swift 3?

@alejandro-isaza I just noticed that Surge doesn't specify any Swift language requirements in the README (though we do have a .swift-version file). It'd be great to make the Swift (and Xcode) version requirements explicit.

[pohetsn]

I see. Thanks for your prompt response.

If I type swift --version, it returns

Apple Swift version 4.0.3 (swiftlang-900.0.74.1 clang-900.0.39.2)
Target: x86_64-apple-macosx10.9

But how should I make sure Carthage is using this version? In Xcode Build Settings, I can change Swift Language Version between 3.2 and 4.0. But it doesn't affect the swift version shown in the command line. Sorry I'm new in this. Thanks for your help.

[pohetsn]

Btw, I also tried CocoaPod to install Surge. In Xcode, I had Build settings > Swift Language Version > Swift 4.0. It shows the same error message.

[alejandro-isaza]

I have never seen this. Make sure you have the latest version of CocoaPods. Alternatively if you can share your project I can have a look.

[pohetsn]

My cocoa pods version is 1.5.3. So it is fairly recent. Btw, I tried to install Surge on another machine that uses Xcode 9.4.1 and Swift version 4.1.2, and Surge was installed without any error. I think DistanceIndex was taken out at 4.1 instead of 4.0 (see here). So maybe the .swift-version file should be updated to 4.1?

[alejandro-isaza]

Ah, good catch. That's probably it. Will update to 4.1.

[alejandro-isaza]

Pushed 2.2.0 to CocoaPods

[mattt]

👏 Thanks, @alejandro-isaza!