warnings: Misc simple fixes

- Remove unused value and unnecessary unsafeBitCast

- Fix expression implicitly coerced from 'Any?' to Any

Author: spevans

CoreFoundation/Base.subproj/CFRuntime.c

@@ -1284,6 +1284,7 @@ static bool (*CAS32)(int32_t, int32_t, volatile int32_t *) = OSAtomicCompareAndS
 
 #if DEPLOYMENT_RUNTIME_SWIFT
 extern void swift_retain(void *);
+extern void swift_release(void *);
 #endif
 
 // For "tryR==true", a return of NULL means "failed".
@@ -1399,7 +1400,6 @@ Boolean _CFIsDeallocating(CFTypeRef cf) {
 static void _CFRelease(CFTypeRef CF_RELEASES_ARGUMENT cf) {
 #if DEPLOYMENT_RUNTIME_SWIFT
     // We always call through to swift_release, since all CFTypeRefs are at least _NSCFType objects
-    extern void swift_release(void *);
     swift_release((void *)cf);
 #else
 

Foundation/CharacterSet.swift

@@ -486,7 +486,7 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
 
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSCharacterSet {
-        return unsafeBitCast(_wrapped, to: NSCharacterSet.self)
+        return _wrapped
     }
 
     public static func _forceBridgeFromObjectiveC(_ input: NSCharacterSet, result: inout CharacterSet?) {

Foundation/NSKeyedArchiver.swift

@@ -376,7 +376,7 @@ open class NSKeyedArchiver : NSCoder {
         if objv == nil {
             return true // always have a null reference
         } else {
-            return self._objRefMap[_SwiftValue.store(objv)] != nil
+            return self._objRefMap[_SwiftValue.store(objv!)] != nil
         }
     }
 

Foundation/NSKeyedUnarchiver.swift

@@ -387,7 +387,7 @@ open class NSKeyedUnarchiver : NSCoder {
         }
 
         // check replacement cache
-        object = self._replacementMap[_SwiftValue.store(decodedObject)]
+        object = self._replacementMap[_SwiftValue.store(decodedObject!)]
         if object != nil {
             return object
         }

Foundation/NSString.swift

@@ -286,7 +286,7 @@ open class NSString : NSObject, NSCopying, NSMutableCopying, NSSecureCoding, NSC
     internal var _fastContents: UnsafePointer<UniChar>? {
         if type(of: self) == NSString.self || type(of: self) == NSMutableString.self {
             if !_storage._core.isASCII {
-                return unsafeBitCast(_storage._core.startUTF16, to: UnsafePointer<UniChar>.self)
+                return UnsafePointer<UniChar>(_storage._core.startUTF16)
             }
         }
         return nil

TestFoundation/TestNSURLSession.swift

@@ -428,7 +428,7 @@ extension DataTask : URLSessionDataDelegate {
 
 extension DataTask : URLSessionTaskDelegate {
     public func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
-         guard let e = error as? URLError else { return }
+         guard (error as? URLError) != nil else { return }
          dataTaskExpectation.fulfill()
          if let cancellation = cancelExpectation {
              cancellation.fulfill()