Homebrew build fails

[dctucker]

==> xcodebuild -workspace slash.xcodeproj/project.xcworkspace -derivedDataPath prefix.to_s -configuration Release -scheme slash SYMROOT=/usr/local/Cellar/slash/0.1.0/Build
Last 15 lines from /Users/dctucker/Library/Logs/Homebrew/slash/01.xcodebuild:
                                            ^
/tmp/slash-20180731-33109-1tyxt8r/slash-0.1.0/Sources/SlackOAuth2.swift:62:45: warning: 'sendSynchronousRequest(_:returning:)' was deprecated in OS X 10.11: Use [NSURLSession dataTaskWithRequest:completionHandler:] (see NSURLSession.h
                        try NSURLConnection.sendSynchronousRequest(URLRequest(url: url), returning: nil))
                                            ^
/tmp/slash-20180731-33109-1tyxt8r/slash-0.1.0/Sources/TextLayout.swift:59:40: warning: 'characters' is deprecated: Please use String or Substring directly
            for character in span.text.characters {
                                       ^

** BUILD FAILED **

The following build commands failed:
    CompileSwift normal x86_64
    CompileSwiftSources normal x86_64 com.apple.xcode.tools.swift.compiler
(2 failures)

Do not report this issue to Homebrew/brew or Homebrew/core!

[dctucker]

01.xcodebuild.txt

[dctucker]

/tmp/slash-20180731-33109-1tyxt8r/slash-0.1.0/Sources/Server.swift:326:70: error: @escaping attribute may only be used in function parameter position
    func serve(_ callback: @escaping ((request: Request, responder: @escaping ((Response) -> Void))) -> Void) throws {
                                                                    ~^~~~~~~~~