Address ambiguity in bare Future init for conditional Task conformance

Deferred.xcodeproj/project.pbxproj

@@ -176,6 +176,9 @@
 		DB647574209652DC00F67EA1 /* DeferredQueue.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB647572209652DC00F67EA1 /* DeferredQueue.swift */; };
 		DB647575209652DC00F67EA1 /* DeferredQueue.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB647572209652DC00F67EA1 /* DeferredQueue.swift */; };
 		DB647576209652DC00F67EA1 /* DeferredQueue.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB647572209652DC00F67EA1 /* DeferredQueue.swift */; };
+		DB78F5EC215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB78F5EB215C4C5700D07CC6 /* TaskProtocolTests.swift */; };
+		DB78F5ED215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB78F5EB215C4C5700D07CC6 /* TaskProtocolTests.swift */; };
+		DB78F5EE215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB78F5EB215C4C5700D07CC6 /* TaskProtocolTests.swift */; };
 		DB79ED6B214F0DF900E0FDEB /* Task.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB79ED6A214F0DF900E0FDEB /* Task.swift */; };
 		DB79ED6C214F0DF900E0FDEB /* Task.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB79ED6A214F0DF900E0FDEB /* Task.swift */; };
 		DB79ED6D214F0DF900E0FDEB /* Task.swift in Sources */ = {isa = PBXBuildFile; fileRef = DB79ED6A214F0DF900E0FDEB /* Task.swift */; };
@@ -297,6 +300,7 @@
 		DB55F1FD1D96968E00FC1439 /* TaskAsyncTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TaskAsyncTests.swift; sourceTree = "<group>"; };
 		DB55F20B1D969A1B00FC1439 /* FutureTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FutureTests.swift; sourceTree = "<group>"; };
 		DB647572209652DC00F67EA1 /* DeferredQueue.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeferredQueue.swift; sourceTree = "<group>"; };
+		DB78F5EB215C4C5700D07CC6 /* TaskProtocolTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TaskProtocolTests.swift; sourceTree = "<group>"; };
 		DB79ED6A214F0DF900E0FDEB /* Task.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Task.swift; sourceTree = "<group>"; };
 		DB79ED6F214F105400E0FDEB /* TaskUpon.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TaskUpon.swift; sourceTree = "<group>"; };
 		DB79ED74214F1BE900E0FDEB /* TaskPromise.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TaskPromise.swift; sourceTree = "<group>"; };
@@ -479,6 +483,7 @@
 				DB55F1F71D96968E00FC1439 /* ResultRecoveryTests.swift */,
 				DB55F1FD1D96968E00FC1439 /* TaskAsyncTests.swift */,
 				EBEB828C1DC4A79A00B7E089 /* TaskComprehensiveTests.swift */,
+				DB78F5EB215C4C5700D07CC6 /* TaskProtocolTests.swift */,
 				DB55F1F81D96968E00FC1439 /* TaskResultTests.swift */,
 				DB55F1FC1D96968E00FC1439 /* TaskTests.swift */,
 				DB55F1F91D96968E00FC1439 /* VoidResultTests.swift */,
@@ -804,6 +809,7 @@
 				DB126D621E5368B900054E95 /* FutureCustomExecutorTests.swift in Sources */,
 				DB126D611E5368B900054E95 /* ExistentialFutureTests.swift in Sources */,
 				DB126D681E5368B900054E95 /* ResultRecoveryTests.swift in Sources */,
+				DB78F5EC215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */,
 				DB34FC902096D335005D5B82 /* ObjectDeferredTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -871,6 +877,7 @@
 				DB126D721E5368B900054E95 /* FutureCustomExecutorTests.swift in Sources */,
 				DB126D711E5368B900054E95 /* ExistentialFutureTests.swift in Sources */,
 				DB126D781E5368B900054E95 /* ResultRecoveryTests.swift in Sources */,
+				DB78F5ED215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */,
 				DB34FC912096D335005D5B82 /* ObjectDeferredTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -938,6 +945,7 @@
 				DB126D821E5368BA00054E95 /* FutureCustomExecutorTests.swift in Sources */,
 				DB126D811E5368BA00054E95 /* ExistentialFutureTests.swift in Sources */,
 				DB126D881E5368BA00054E95 /* ResultRecoveryTests.swift in Sources */,
+				DB78F5EE215C4C5700D07CC6 /* TaskProtocolTests.swift in Sources */,
 				DB34FC922096D335005D5B82 /* ObjectDeferredTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

Sources/Task/ExistentialTask.swift

@@ -64,7 +64,7 @@ public final class Task<SuccessValue>: NSObject {
 
     /// Creates a task whose `upon(_:execute:)` methods use those of `base`.
     public convenience init<Wrapped: TaskProtocol>(_ wrapped: Wrapped, progress: Progress) where Wrapped.SuccessValue == SuccessValue {
-        let future = Future<Result>(wrapped)
+        let future = Future<Result>(resultFrom: wrapped)
         self.init(future, progress: progress)
     }
 
@@ -144,7 +144,7 @@ extension Task {
     /// `cancellation` will be called asynchronously, but not on any specific
     /// queue. If you must do work on a specific queue, schedule work on it.
     public convenience init<Wrapped: TaskProtocol>(_ wrapped: Wrapped, uponCancel cancellation: (() -> Void)? = nil) where Wrapped.SuccessValue == SuccessValue {
-        let future = Future<Result>(wrapped)
+        let future = Future<Result>(resultFrom: wrapped)
         #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
         let progress = Progress.wrappingSuccess(of: wrapped, uponCancel: cancellation)
         self.init(future, progress: progress)

Sources/Task/Task.swift

@@ -83,7 +83,7 @@ extension Future: TaskProtocol where Value: Either, Value.Left == Error {
     public typealias SuccessValue = Value.Right
 
     /// Create a future having the same underlying task as `other`.
-    public init<Wrapped: TaskProtocol>(_ wrapped: Wrapped) where Wrapped.SuccessValue == SuccessValue, Wrapped.FailureValue == FailureValue {
+    public init<Wrapped: TaskProtocol>(resultFrom wrapped: Wrapped) where Wrapped.SuccessValue == SuccessValue {
         self = wrapped as? Future<Value> ?? wrapped.every {
             $0.withValues(ifLeft: Value.init(left:), ifRight: Value.init(right:))
         }

Tests/TaskTests/TaskProtocolTests.swift

@@ -0,0 +1,27 @@
+//
+//  TaskProtocolTests.swift
+//  Deferred
+//
+//  Created by Zachary Waldowski on 9/26/18.
+//  Copyright © 2018 Big Nerd Ranch. Licensed under MIT.
+//
+
+import XCTest
+
+#if SWIFT_PACKAGE
+import Deferred
+import Task
+#else
+import Deferred
+#endif
+
+class TaskProtocolTests: XCTestCase {
+
+    func testConditionalFutureInitAmbiguity() {
+        // This is a compiler-time check only.
+        typealias Result = TaskResult<Int>
+        let deferred = Deferred<Result>()
+        _ = Future(deferred)
+    }
+
+}