diff --git a/Sources/Data.swift b/Sources/Data.swift
index 4f09d04..693e7e4 100644
--- a/Sources/Data.swift
+++ b/Sources/Data.swift
@@ -34,7 +34,7 @@ extension Data: RangeReplaceableCollection, MutableCollection {
     }
 
     #if swift(>=3.0)
-        public init<S : Sequence where S.Iterator.Element == Byte>(_ elements: S) {
+        public init<S : Sequence>(_ elements: S) where S.Iterator.Element == Byte {
             self.init(Array(elements))
         }
     #else
@@ -44,7 +44,7 @@ extension Data: RangeReplaceableCollection, MutableCollection {
     #endif
 
     #if swift(>=3.0)
-        public mutating func replaceSubrange<C : Collection where C.Iterator.Element == Byte>(_ subRange: Range<Int>, with newElements: C) {
+        public mutating func replaceSubrange<C : Collection>(_ subRange: Range<Int>, with newElements: C) where C.Iterator.Element == Byte {
             self.bytes.replaceSubrange(subRange, with: newElements)
         }
     #else
@@ -123,7 +123,7 @@ public func == (lhs: Data, rhs: Data) -> Bool {
 }
 
 #if swift(>=3.0)
-    public func += <S : Sequence where S.Iterator.Element == Byte>(lhs: inout Data, rhs: S) {
+    public func += <S : Sequence>(lhs: inout Data, rhs: S) where S.Iterator.Element == Byte {
         return lhs.bytes += rhs
     }
 #else
@@ -174,7 +174,7 @@ extension String: DataConvertible {
 
             loop: while true {
                 switch decoder.decode(&generator) {
-                case .scalarValue(let char): string.append(char)
+                case .scalarValue(let char): string.unicodeScalars.append(char)
                 case .emptyInput: break loop
                 case .error: throw StringError()
                 }