selfInSscapingClosure.swift

class Coder {
    var isCoding = false
    func perform(_ work: @escaping () -> Void) {
        work()
    }
    
    func startCoding() {
        perform { [self] in // <- Fix-it: capture 'self' explicitly to enable implicit 'self' in this closure. Fix-it: insert '[self] in'
            isCoding = true
        }
    }
}

let newCoder = Coder()
newCoder.startCoding()