From b9c65ddb7ae8fe2779853ef8cc21679d39efa88b Mon Sep 17 00:00:00 2001
From: NachoSoto <ignaciosoto90@gmail.com>
Date: Mon, 3 Jun 2019 15:46:57 -0700
Subject: [PATCH 1/2] Signal: using Signal.Event.promoteValue

This fixes compilation on `Xcode 11` / `Swift 5.1`.
---
 Sources/Event.swift  | 26 ++++++++++++++++----------
 Sources/Signal.swift |  2 +-
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/Sources/Event.swift b/Sources/Event.swift
index 578a604dc..f2886f53b 100644
--- a/Sources/Event.swift
+++ b/Sources/Event.swift
@@ -1015,17 +1015,23 @@ extension Signal.Event where Value == Never {
 	internal static func promoteValue<U>(_: U.Type) -> Transformation<U, Error> {
 		return { action, _ in
 			return { event in
-				switch event {
-				case .value:
-					fatalError("Never is impossible to construct")
-				case let .failed(error):
-					action(.failed(error))
-				case .completed:
-					action(.completed)
-				case .interrupted:
-					action(.interrupted)
-				}
+                action(event.promoteValue())
 			}
 		}
 	}
 }
+
+extension Signal.Event where Value == Never {
+	internal func promoteValue<U>() -> Signal<U, Error>.Event {
+        switch event {
+        case .value:
+            fatalError("Never is impossible to construct")
+        case let .failed(error):
+            return .failed(error)
+        case .completed:
+            return .completed
+        case .interrupted:
+            return .interrupted
+        }
+    }
+}
diff --git a/Sources/Signal.swift b/Sources/Signal.swift
index 5f361d845..039bc9a83 100644
--- a/Sources/Signal.swift
+++ b/Sources/Signal.swift
@@ -1848,7 +1848,7 @@ extension Signal {
 			}
 
 			for (index, action) in builder.startHandlers.enumerated() where !lifetime.hasEnded {
-				lifetime += action(index, strategy) { observer.send($0.map { _ in fatalError() }) }
+				lifetime += action(index, strategy) { observer.send($0.promoteValue()) }
 			}
 		}
 	}

From a1f6c70715672f7e88a7d8c34aec12150ee1b90a Mon Sep 17 00:00:00 2001
From: Matt Diephouse <matt@diephouse.com>
Date: Tue, 4 Jun 2019 07:27:01 -0400
Subject: [PATCH 2/2] Fix indentation

---
 Sources/Event.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/Event.swift b/Sources/Event.swift
index f2886f53b..7c2495c52 100644
--- a/Sources/Event.swift
+++ b/Sources/Event.swift
@@ -1015,7 +1015,7 @@ extension Signal.Event where Value == Never {
 	internal static func promoteValue<U>(_: U.Type) -> Transformation<U, Error> {
 		return { action, _ in
 			return { event in
-                action(event.promoteValue())
+				action(event.promoteValue())
 			}
 		}
 	}