Xcode9.3 (Swift4.1)+ RxSwiftでコンパイラーの最適化時にクラッシュするみたいです。リリースする際にはお気をつけて... https://github.com/ReactiveX/RxSwift/issues/1555 https://bugs.swift.org/browse/SR-7064

Runtime errors with Xcode 9.3b1 / Swift 4.1. (combineLatest/zip op...

Short description of the issue: combineLatest/zip operators fail at runtime with latest Xcode 9.3b1 / Swift 4.1 running against iOS 11.3 OR 11.2. Expected outcome: combineLatest/zip operators execu...