Open Radar

 
Please provide a descriptive title for your feedback
Segmentation fault while type checking complex expression
Which product are you seeing an issue with?
Developer Tools
Which area are you seeing an issue with?
Description
Please describe the issue and what steps we can take to reproduce it
Summary:

When trying to type check a complex expression the editor crashes

Steps to Reproduce:

Using this extension

extension Array where Element == URLQueryItem {
    
    subscript(name: String) -> String? {
        return first(where: { $0.name == name })?.value
    }
    
}

if let ids = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems?["ids"]?.split(separator: ",").flatMap(Int.init) {
    // do stuff
}

the editor crashes

Even if I include the correct type, it still crashes

if let ids: [Int] = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems?["ids"]?.split(separator: ",").flatMap(Int.init) {
    // do stuff
}

Expected Results:

The editor should resolve the type to Array<Int>

Actual Results:

The editor crashes with segmentation fault 11

Version/Build:

Xcode Version 10.2 (10E125)

Configuration:

MacBook Pro Retina 15 Mid 2012
macOS Mojave 10.14.4 (18E226)