Fixed Failable<Sequence>: Sequence conformance for Swift 5 updates

Sources/Failable/Failable+Helpers/Failable+Optional.swift

@@ -27,10 +27,10 @@ extension Failable {
 
 /// See [`Optional.??(_:_:)`](https://developer.apple.com/documentation/swift/1539917).
 public func ?? <T, V>(optional: Failable<T?, V>, defaultValue: @autoclosure () throws -> T) rethrows -> T {
-    return try optional.value ?? defaultValue
+    return try optional.value ?? defaultValue()
 }
 
 /// See [`Optional.??(_:_:)`](https://developer.apple.com/documentation/swift/1541015).
 public func ?? <T, V>(optional: Failable<T?, V>, defaultValue: @autoclosure () throws -> T?) rethrows -> T? {
-    return try optional.value ?? defaultValue
+    return try optional.value ?? defaultValue()
 }

Sources/Failable/Failable+Helpers/Failable+Sequence.swift

@@ -1,5 +1,4 @@
 extension Failable: Sequence where T: Sequence {
-    
     /// See [`Sequence.Element`](https://developer.apple.com/documentation/swift/sequence/2908099-element).
     public typealias Element = T.Element
     
@@ -13,38 +12,38 @@ extension Failable: Sequence where T: Sequence {
     
     /// See [`Sequence.split(separator:maxSplits:omittingEmptySubsequences:)`](https://developer.apple.com/documentation/swift/sequence/2908109-split).
     public func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator isSeparator: (T.Element) throws -> Bool) rethrows
-        -> [T.SubSequence]
+        -> [ArraySlice<T.Element>]
     {
         return try self.value.split(maxSplits: maxSplits, omittingEmptySubsequences: omittingEmptySubsequences, whereSeparator: isSeparator)
     }
     
     /// See [`Sequence.suffix(_:)`](https://developer.apple.com/documentation/swift/sequence/2965540-suffix).
-    public func suffix(_ maxLength: Int) -> T.SubSequence {
+    public func suffix(_ maxLength: Int) -> [T.Element] {
         return self.value.suffix(maxLength)
     }
     
     /// See [`Sequence.prefix(while:)`](https://developer.apple.com/documentation/swift/sequence/2965528-prefix)
-    public func prefix(while predicate: (T.Element) throws -> Bool) rethrows -> T.SubSequence {
+    public func prefix(while predicate: (T.Element) throws -> Bool) rethrows -> [T.Element] {
         return try self.value.prefix(while: predicate)
     }
     
     /// See [`Sequence.prefix(_:)`](https://developer.apple.com/documentation/swift/sequence/2965524-prefix).
-    public func prefix(_ maxLength: Int) -> T.SubSequence {
+    public func prefix(_ maxLength: Int) -> PrefixSequence<T> {
         return self.value.prefix(maxLength)
     }
     
     /// See [`Sequence.drop(while:)`](https://developer.apple.com/documentation/swift/sequence/2965501-drop).
-    public func drop(while predicate: (T.Element) throws -> Bool) rethrows -> T.SubSequence {
+    public func drop(while predicate: (T.Element) throws -> Bool) rethrows -> DropWhileSequence<T> {
         return try self.value.drop(while: predicate)
     }
     
     /// See [`Sequence.dropLast`](https://developer.apple.com/documentation/swift/sequence/2965508-droplast).
-    public func dropLast(_ k: Int) -> T.SubSequence {
+    public func dropLast(_ k: Int) -> [T.Element] {
         return self.value.dropLast(k)
     }
     
     /// See [`Sequence.dropFirst(_:)`](https://developer.apple.com/documentation/swift/sequence/2965504-dropfirst).
-    public func dropFirst(_ k: Int) -> T.SubSequence {
+    public func dropFirst(_ k: Int) -> DropFirstSequence<T> {
         return self.value.dropFirst(k)
     }
 }