Work around type inference failure for flatMap

Author: jspahrsummers

ReactiveTask/Task.swift

@@ -267,9 +267,12 @@ public func launchTask(taskDescription: TaskDescription, standardOutput: SinkOf<
 			}
 		}
 
-		SignalProducer(result: Pipe.create())
-			|> zipWith(SignalProducer(result: Pipe.create()))
-			|> flatMap(.Merge) { stdoutPipe, stderrPipe -> SignalProducer<NSData, ReactiveTaskError> in
+		let pipes = SignalProducer(result: Pipe.create()) |> zipWith(SignalProducer(result: Pipe.create()))
+
+		// The Swift compiler can't figure out that we're applying this to
+		// a Producer when using |> :(
+		flatMap(.Merge,
+			{ stdoutPipe, stderrPipe -> SignalProducer<NSData, ReactiveTaskError> in
 				let stdoutProducer = aggregateDataReadFromPipe(stdoutPipe, standardOutput)
 				let stderrProducer = aggregateDataReadFromPipe(stderrPipe, standardError)
 
@@ -315,7 +318,7 @@ public func launchTask(taskDescription: TaskDescription, standardOutput: SinkOf<
 							return .failure(.ShellTaskFailed(exitCode: terminationStatus, standardError: errorString))
 						}
 					}
-			}
+			})(producer: pipes)
 			|> startWithSignal { signal, taskDisposable in
 				disposable.addDisposable(taskDisposable)
 				signal.observe(observer)