empty_enum_arguments not triggering for if case

[lordzsolt]

New Issue Checklist

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

Describe the bug

This is not causing a violation, but it should:

enum Result<Success, Failure> {
    case success(Success)
    case failure(Failure)
}

let result: Result<Int, Error> = .success(3)
if case .success↓(_) = result {
    ...
}

If you write it out in a switch, it will trigger a violation:

switch result {
case .success↓(_):
    ...
case .failure↓(_):
    ...
}

Environment

• SwiftLint version: 0.38.2

• Installation method used: homebrew

• Paste your configuration file:
  Default configuration

• Are you using nested configurations: No

• Which Xcode version are you using (check xcodebuild -version): 11.3.1

• Do you have a sample that shows the issue: Check above