Fix errors due to latest Swift 4 version

This closes #42.

Author: nvzqz

Sources/RandomKit/Extensions/Swift/Integer+RandomKit.swift

@@ -356,7 +356,7 @@ extension UnsignedInteger where Self: RandomWithMaxWidth & RandomWithExactWidth
     /// Generates a random value of `Self` with an exact width using `randomGenerator`.
     public static func random<R: RandomGenerator>(withExactWidth width: Int, using randomGenerator: inout R) -> Self {
         guard width > 0 else { return 0 }
-        return random(withMaxWidth: width, using: &randomGenerator) | (1 &<< Self(width - 1))
+        return random(withMaxWidth: width, using: &randomGenerator) | Self(1 &<< Self(width - 1))
     }
 }
 
@@ -577,7 +577,7 @@ extension Int8: UnsafeRandom, RandomWithMax, RandomWithMin, RandomToValue, Rando
 #if swift(>=3.2)
 extension UnsignedInteger where Self: FixedWidthInteger {
     fileprivate var _resigned: Self {
-        let bits = Self(extendingOrTruncating: MemoryLayout<Self>.size * 8 - 1)
+        let bits = Self(truncatingIfNeeded: MemoryLayout<Self>.size * 8 - 1)
         return self ^ (1 &<< bits)
     }
 }

Sources/RandomKit/Types/RandomGenerator/ARC4Random.swift

@@ -64,7 +64,7 @@ public final class ARC4Random: RandomGenerator {
     /// Generates a random unsigned 16-bit integer.
     public func random16() -> UInt16 {
         #if swift(>=3.2)
-            return UInt16(extendingOrTruncating: random32())
+            return UInt16(truncatingIfNeeded: random32())
         #else
             return UInt16(truncatingBitPattern: random32())
         #endif
@@ -73,7 +73,7 @@ public final class ARC4Random: RandomGenerator {
     /// Generates a random unsigned 8-bit integer.
     public func random8() -> UInt8 {
         #if swift(>=3.2)
-            return UInt8(extendingOrTruncating: random32())
+            return UInt8(truncatingIfNeeded: random32())
         #else
             return UInt8(truncatingBitPattern: random32())
         #endif

Sources/RandomKit/Types/RandomGenerator/ChaCha.swift

@@ -131,10 +131,10 @@ public struct ChaCha: RandomBytesGenerator, Seedable, SeedableFromSequence, Seed
     /// Sets the internal 128-bit counter.
     public mutating func setCounter(low: UInt64, high: UInt64) {
         #if swift(>=3.2)
-            _state.12 = UInt32(extendingOrTruncating: low)
-            _state.13 = UInt32(extendingOrTruncating: low &>> 32)
-            _state.14 = UInt32(extendingOrTruncating: high)
-            _state.15 = UInt32(extendingOrTruncating: high &>> 32)
+            _state.12 = UInt32(truncatingIfNeeded: low)
+            _state.13 = UInt32(truncatingIfNeeded: low &>> 32)
+            _state.14 = UInt32(truncatingIfNeeded: high)
+            _state.15 = UInt32(truncatingIfNeeded: high &>> 32)
         #else
             _state.12 = UInt32(truncatingBitPattern: low)
             _state.13 = UInt32(truncatingBitPattern: low >> 32)

Sources/RandomKit/Types/RandomGenerator/RandomBytesGenerator.swift

@@ -46,7 +46,7 @@ extension RandomBytesGenerator where Bytes == UInt64 {
     /// Generates a random unsigned 32-bit integer.
     public mutating func random32() -> UInt32 {
         #if swift(>=3.2)
-            return UInt32(extendingOrTruncating: randomBytes())
+            return UInt32(truncatingIfNeeded: randomBytes())
         #else
             return UInt32(truncatingBitPattern: randomBytes())
         #endif
@@ -55,7 +55,7 @@ extension RandomBytesGenerator where Bytes == UInt64 {
     /// Generates a random unsigned 16-bit integer.
     public mutating func random16() -> UInt16 {
         #if swift(>=3.2)
-            return UInt16(extendingOrTruncating: randomBytes())
+            return UInt16(truncatingIfNeeded: randomBytes())
         #else
             return UInt16(truncatingBitPattern: randomBytes())
         #endif
@@ -64,7 +64,7 @@ extension RandomBytesGenerator where Bytes == UInt64 {
     /// Generates a random unsigned 8-bit integer.
     public mutating func random8() -> UInt8 {
         #if swift(>=3.2)
-            return UInt8(extendingOrTruncating: randomBytes())
+            return UInt8(truncatingIfNeeded: randomBytes())
         #else
             return UInt8(truncatingBitPattern: randomBytes())
         #endif
@@ -87,7 +87,7 @@ extension RandomBytesGenerator where Bytes == UInt32 {
     /// Generates a random unsigned 16-bit integer.
     public mutating func random16() -> UInt16 {
         #if swift(>=3.2)
-            return UInt16(extendingOrTruncating: randomBytes())
+            return UInt16(truncatingIfNeeded: randomBytes())
         #else
             return UInt16(truncatingBitPattern: randomBytes())
         #endif
@@ -96,7 +96,7 @@ extension RandomBytesGenerator where Bytes == UInt32 {
     /// Generates a random unsigned 8-bit integer.
     public mutating func random8() -> UInt8 {
         #if swift(>=3.2)
-            return UInt8(extendingOrTruncating: randomBytes())
+            return UInt8(truncatingIfNeeded: randomBytes())
         #else
             return UInt8(truncatingBitPattern: randomBytes())
         #endif

Sources/RandomKit/Types/RandomGenerator/ReseedingRandomGenerator.swift

@@ -109,11 +109,10 @@ extension Int {
     fileprivate func _saturatingAddPositive(_ other: Int) -> Int {
         #if swift(>=3.2)
             let (result, overflow) = addingReportingOverflow(other)
-            return overflow == .overflow ? .max : result
         #else
             let (result, overflow) = Int.addWithOverflow(self, other)
-            return overflow ? .max : result
         #endif
+        return overflow ? .max : result
     }
 }