class_delegate_protocol incorrectly triggering with Xcode 9.1 beta (9B37)

[danj-stripe]

New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues

Bug Report

Complete output when running SwiftLint, including the stack trace and command used

$ echo 'protocol FooDelegate: class {}' | swiftlint --use-stdin --config swiftlint.yml 
Loading configuration from 'swiftlint.yml'
<nopath>:1:1: warning: Class Delegate Protocol Violation: Delegate protocols should be class-only so they can be weakly referenced. (class_delegate_protocol)
Done linting! Found 1 violation, 0 serious in 1 file.

Environment

• SwiftLint version (run swiftlint version to be sure)?

0.22.0

• Installation method used (Homebrew, CocoaPods, building from source, etc)?

Homebrew

• Paste your configuration file:

whitelist_rules:
  - class_delegate_protocol

• Are you using nested configurations?
  If so, paste their relative paths and respective contents.

No

• Which Xcode version are you using (check xcode-select -p)?

$ xcode-select -p
/Applications/Xcode-beta.app/Contents/Developer
$ xcodebuild -version
Xcode 9.1
Build version 9B37

• Do you have a sample that shows the issue? Run echo "[string here]" | swiftlint lint --no-cache --use-stdin --enable-all-rules
  to quickly test if your example is really demonstrating the issue. If your example is more
  complex, you can use swiftlint lint --path [file here] --no-cache --enable-all-rules.

// This triggers a violation:
protocol FooDelegate: class {}

More info

Upgrading to 9.1 also started showing (actual) violations of the colon rule for protocol declarations (I think that's be a good thing). Maybe something changed re: the parse tree for protocols?