False positive: unused_declaration flagging projectedValue of property wrapper

Describe the bug

Swiftlint is identifying the projectedValue of a property wrapper as unused.

Environment

• SwiftLint version (run swiftlint version to be sure)? 0.39.2

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

• Are you using nested configurations? No

• Which Xcode version are you using (check xcodebuild -version)? Xcode 11.3.1 Build version 11C505

• Do you have a sample that shows the issue?

@propertyWrapper
final class LockedWhenRead<Value: Equatable> {
    /// Allows access outside of private scope.
    var projectedValue: LockedWhenRead<Value> { return self }

    var wrappedValue: Value {
        get { self.getAndLockValue() }
        set { self.storeAndSet(newValue) }
    }

    private func getAndLockValue() -> Value {
        ...
    }

    private func storeAndSet(_ newValue: Value) {
        ...
    }
}

Reproduce the reported example with SwiftLint 0.39.2 and the unused_declaration rule, focusing on the property wrapper's projectedValue. Trace how the rule classifies projectedValue and verify the fix against the sample so that a valid projectedValue is no longer reported as unused.