stdlib: Remove _isBridgedToObjectiveC from _ObjectiveCBridgeable.

All generic bridgeable types can bridge for all their instantiations now. Removing this ferrets out some now-unnecessary traps that check for unbridgeable parameter types.

docs/Runtime.md

@@ -251,7 +251,6 @@ process start and the function returns.
 should be implementable in the standard library now.
 
 ```
-0000000000003b60 T _swift_bridgeNonVerbatimFromObjectiveC
 0000000000003c80 T _swift_bridgeNonVerbatimFromObjectiveCConditional
 00000000000037e0 T _swift_bridgeNonVerbatimToObjectiveC
 00000000000039c0 T _swift_getBridgedNonVerbatimObjectiveCType

stdlib/public/SDK/Dispatch/Data.swift

@@ -262,10 +262,6 @@ public struct DispatchDataIterator : IteratorProtocol, Sequence {
 }
 
 extension DispatchData {
-	public static func _isBridgedToObjectiveC() -> Bool {
-		return true
-	}
-
 	@_semantics("convertToObjectiveC")
 	public func _bridgeToObjectiveC() -> __DispatchData {
 		return unsafeBitCast(__wrapped, to: __DispatchData.self)

stdlib/public/SDK/Foundation/AffineTransform.swift

@@ -264,10 +264,6 @@ extension AffineTransform : ReferenceConvertible, Hashable, CustomStringConverti
 }
 
 extension AffineTransform : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSAffineTransform.self
     }

stdlib/public/SDK/Foundation/Calendar.swift

@@ -1082,10 +1082,6 @@ public struct Calendar : CustomStringConvertible, CustomDebugStringConvertible,
 }
 
 extension Calendar : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSCalendar {
         return _handle._copiedReference()

stdlib/public/SDK/Foundation/CharacterSet.swift

@@ -439,10 +439,6 @@ public struct CharacterSet : ReferenceConvertible, Equatable, Hashable, SetAlgeb
 
 // MARK: Objective-C Bridging
 extension CharacterSet : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSCharacterSet.self
     }

stdlib/public/SDK/Foundation/Data.swift

@@ -678,10 +678,6 @@ public struct Data : ReferenceConvertible, CustomStringConvertible, Equatable, H
 
 /// Provides bridging functionality for struct Data to class NSData and vice-versa.
 extension Data : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSData {
         return unsafeBitCast(_wrapped, to: NSData.self)

stdlib/public/SDK/Foundation/Date.swift

@@ -229,10 +229,6 @@ public struct Date : ReferenceConvertible, Comparable, Equatable, CustomStringCo
 }
 
 extension Date : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSDate {
         return NSDate(timeIntervalSinceReferenceDate: _time)

stdlib/public/SDK/Foundation/DateComponents.swift

@@ -292,10 +292,6 @@ public struct DateComponents : ReferenceConvertible, Hashable, Equatable, _Mutab
 // MARK: - Bridging
 
 extension DateComponents : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSDateComponents.self
     }

stdlib/public/SDK/Foundation/DateInterval.swift

@@ -183,10 +183,6 @@ public struct DateInterval : ReferenceConvertible, Comparable, Hashable {
 
 @available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
 extension DateInterval : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSDateInterval.self
     }

stdlib/public/SDK/Foundation/Decimal.swift

@@ -436,10 +436,6 @@ extension Decimal : CustomStringConvertible {
 }
 
 extension Decimal : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSDecimalNumber {
         return NSDecimalNumber(decimal: self)

stdlib/public/SDK/Foundation/Foundation.swift

@@ -86,10 +86,6 @@ extension String {
 }
 
 extension String : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   @_semantics("convertToObjectiveC")
   public func _bridgeToObjectiveC() -> NSString {
     // This method should not do anything extra except calling into the
@@ -132,10 +128,6 @@ extension String : _ObjectiveCBridgeable {
 // back to a specific numeric type requires a cast.
 // FIXME: Incomplete list of types.
 extension Int : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self = number.intValue
   }
@@ -168,10 +160,6 @@ extension Int : _ObjectiveCBridgeable {
 }
 
 extension UInt : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self = number.uintValue
   }
@@ -204,10 +192,6 @@ extension UInt : _ObjectiveCBridgeable {
 }
 
 extension Float : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self = number.floatValue
   }
@@ -240,10 +224,6 @@ extension Float : _ObjectiveCBridgeable {
 }
 
 extension Double : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self = number.doubleValue
   }
@@ -276,10 +256,6 @@ extension Double : _ObjectiveCBridgeable {
 }
 
 extension Bool: _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self = number.boolValue
   }
@@ -313,10 +289,6 @@ extension Bool: _ObjectiveCBridgeable {
 
 // CGFloat bridging.
 extension CGFloat : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public init(_ number: NSNumber) {
     self.native = CGFloat.NativeType(number)
   }
@@ -408,10 +380,6 @@ extension Array : _ObjectiveCBridgeable {
         unsafeBitCast(_cocoaArray.copy() as AnyObject, to: _NSArrayCore.self))
   }
 
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return Swift._isBridgedToObjectiveC(Element.self)
-  }
-
   @_semantics("convertToObjectiveC")
   public func _bridgeToObjectiveC() -> NSArray {
     return unsafeBitCast(self._buffer._asCocoaArray() as AnyObject, to: NSArray.self)
@@ -570,11 +538,6 @@ extension Dictionary : _ObjectiveCBridgeable {
     return result != nil
   }
 
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return Swift._isBridgedToObjectiveC(Key.self) &&
-           Swift._isBridgedToObjectiveC(Value.self)
-  }
-
   public static func _unconditionallyBridgeFromObjectiveC(
     _ d: NSDictionary?
   ) -> Dictionary {
@@ -850,10 +813,6 @@ extension Set : _ObjectiveCBridgeable {
     })
     return builder.take()
   }
-
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return Swift._isBridgedToObjectiveC(Element.self)
-  }
 }
 
 extension NSDictionary : Sequence {

stdlib/public/SDK/Foundation/IndexPath.swift

@@ -209,10 +209,6 @@ public struct IndexPath : ReferenceConvertible, Equatable, Hashable, MutableColl
 }
 
 extension IndexPath : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSIndexPath.self
     }

stdlib/public/SDK/Foundation/IndexSet.swift

@@ -852,10 +852,6 @@ private func _toNSRange(_ r : Range<IndexSet.Element>) -> NSRange {
 }
 
 extension IndexSet : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSIndexSet.self
     }

stdlib/public/SDK/Foundation/Locale.swift

@@ -441,10 +441,6 @@ public struct Locale : CustomStringConvertible, CustomDebugStringConvertible, Ha
 
 
 extension Locale : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSLocale {
         return _wrapped

stdlib/public/SDK/Foundation/Measurement.swift

@@ -253,10 +253,6 @@ extension Measurement {
 
 @available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
 extension Measurement : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSMeasurement {
         return NSMeasurement(doubleValue: value, unit: unit)

stdlib/public/SDK/Foundation/NSValue.swift

@@ -11,10 +11,6 @@
 //===----------------------------------------------------------------------===//
 
 extension NSRange : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-  
   public func _bridgeToObjectiveC() -> NSValue {
     return NSValue(range: self)
   }

stdlib/public/SDK/Foundation/Notification.swift

@@ -95,10 +95,6 @@ public struct Notification : ReferenceConvertible, Equatable, Hashable {
 }
 
 extension Notification : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSNotification.self
     }

stdlib/public/SDK/Foundation/PersonNameComponents.swift

@@ -87,10 +87,6 @@ public struct PersonNameComponents : ReferenceConvertible, Hashable, Equatable,
 
 @available(OSX 10.11, iOS 9.0, *)
 extension PersonNameComponents : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSPersonNameComponents.self
     }

stdlib/public/SDK/Foundation/TimeZone.swift

@@ -230,10 +230,6 @@ public struct TimeZone : CustomStringConvertible, CustomDebugStringConvertible,
 }
 
 extension TimeZone : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSTimeZone {
         // _wrapped is immutable

stdlib/public/SDK/Foundation/URL.swift

@@ -1124,10 +1124,6 @@ public struct URL : ReferenceConvertible, CustomStringConvertible, Equatable {
 }
 
 extension URL : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSURL {
         return _url

stdlib/public/SDK/Foundation/URLComponents.swift

@@ -316,10 +316,6 @@ public struct URLComponents : ReferenceConvertible, Hashable, CustomStringConver
 }
 
 extension URLComponents : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSURLComponents.self
     }
@@ -384,10 +380,6 @@ public struct URLQueryItem : ReferenceConvertible, Hashable, Equatable, CustomSt
 
 @available(OSX 10.10, iOS 8.0, *)
 extension URLQueryItem : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSURLQueryItem.self
     }

stdlib/public/SDK/Foundation/URLRequest.swift

@@ -247,10 +247,6 @@ public struct URLRequest : ReferenceConvertible, CustomStringConvertible, Equata
 }
 
 extension URLRequest : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     public static func _getObjectiveCType() -> Any.Type {
         return NSURLRequest.self
     }

stdlib/public/SDK/Foundation/UUID.swift

@@ -107,10 +107,6 @@ public struct UUID : ReferenceConvertible, Hashable, Equatable, CustomStringConv
 }
 
 extension UUID : _ObjectiveCBridgeable {
-    public static func _isBridgedToObjectiveC() -> Bool {
-        return true
-    }
-    
     @_semantics("convertToObjectiveC")
     public func _bridgeToObjectiveC() -> NSUUID {
         return reference

stdlib/public/core/ArrayBuffer.swift

@@ -112,13 +112,8 @@ extension _ArrayBuffer {
 
   /// Convert to an NSArray.
   ///
-  /// - Precondition: `_isBridgedToObjectiveC(Element.self)`.
-  ///   O(1) if the element type is bridged verbatim, O(N) otherwise.
+  /// O(1) if the element type is bridged verbatim, O(N) otherwise.
   public func _asCocoaArray() -> _NSArrayCore {
-    _sanityCheck(
-      _isBridgedToObjectiveC(Element.self),
-      "Array element type is not bridged to Objective-C")
-
     return _fastPath(_isNative) ? _native._asCocoaArray() : _nonNative
   }
 

stdlib/public/core/BridgeObjectiveC.swift

@@ -19,14 +19,6 @@
 public protocol _ObjectiveCBridgeable {
   associatedtype _ObjectiveCType : AnyObject
 
-  /// Returns `true` iff instances of `Self` can be converted to
-  /// Objective-C.  Even if this method returns `true`, a given
-  /// instance of `Self._ObjectiveCType` may, or may not, convert
-  /// successfully to `Self`; for example, an `NSArray` will only
-  /// convert successfully to `[String]` if it contains only
-  /// `NSString`s.
-  static func _isBridgedToObjectiveC() -> Bool
-
   /// Convert `self` to Objective-C.
   func _bridgeToObjectiveC() -> _ObjectiveCType
 
@@ -91,6 +83,13 @@ public protocol _ObjectiveCBridgeable {
       -> Self
 }
 
+// TODO: stub for unit testing purposes
+extension _ObjectiveCBridgeable {
+  public static func _isBridgedToObjectiveC() -> Bool {
+    return true
+  }
+}
+
 //===--- Bridging for metatypes -------------------------------------------===//
 
 /// A stand-in for a value of metatype type.
@@ -106,10 +105,6 @@ public struct _BridgeableMetatype: _ObjectiveCBridgeable {
 
   public typealias _ObjectiveCType = AnyObject
 
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return true
-  }
-
   public func _bridgeToObjectiveC() -> AnyObject {
     return value
   }
@@ -149,66 +144,19 @@ public struct _BridgeableMetatype: _ObjectiveCBridgeable {
 // implementations.
 //===----------------------------------------------------------------------===//
 
-/// Attempt to convert `x` to its Objective-C representation.
-///
-/// - If `T` is a class type, it is always bridged verbatim, the function
-///   returns `x`;
-///
-/// - otherwise, `T` conforms to `_ObjectiveCBridgeable`:
-///   + if `T._isBridgedToObjectiveC()` returns `false`, then the
-///     result is empty;
-///   + otherwise, returns the result of `x._bridgeToObjectiveC()`;
-///
-/// - otherwise, the result is empty.
-public func _bridgeToObjectiveC<T>(_ x: T) -> AnyObject? {
-  if _fastPath(_isClassOrObjCExistential(T.self)) {
-    return unsafeBitCast(x, to: AnyObject.self)
-  }
-  return _bridgeNonVerbatimToObjectiveC(x)
-}
-
-public func _bridgeToObjectiveCUnconditional<T>(_ x: T) -> AnyObject {
-  let optResult: AnyObject? = _bridgeToObjectiveC(x)
-  _precondition(optResult != nil,
-      "value failed to bridge from Swift type to a Objective-C type")
-  return optResult!
-}
-
-/// Same as `_bridgeToObjectiveCUnconditional`, but autoreleases the
-/// return value if `T` is bridged non-verbatim.
-func _bridgeToObjectiveCUnconditionalAutorelease<T>(_ x: T) -> AnyObject
-{
-  if _fastPath(_isClassOrObjCExistential(T.self)) {
-    return unsafeBitCast(x, to: AnyObject.self)
-  }
-  guard let bridged = _bridgeNonVerbatimToObjectiveC(x) else {
-    _preconditionFailure(
-      "Dictionary key failed to bridge from Swift type to a Objective-C type")
-  }
-
-  _autorelease(bridged)
-  return bridged
-}
-
-@_silgen_name("_swift_bridgeNonVerbatimToObjectiveC")
-func _bridgeNonVerbatimToObjectiveC<T>(_ x: T) -> AnyObject?
-
 /// Bridge an arbitrary value to an Objective-C object.
 ///
 /// - If `T` is a class type, it is always bridged verbatim, the function
 ///   returns `x`;
 ///
-/// - otherwise, `T` conforms to `_ObjectiveCBridgeable`:
-///   + if `T._isBridgedToObjectiveC()` returns `false`, then
-///     we fall back to boxing (below);
-///   + otherwise, returns the result of `x._bridgeToObjectiveC()`;
+/// - otherwise, if `T` conforms to `_ObjectiveCBridgeable`,
+///   returns the result of `x._bridgeToObjectiveC()`;
 ///
 /// - otherwise, we use **boxing** to bring the value into Objective-C.
 ///   The value is wrapped in an instance of a private Objective-C class
 ///   that is `id`-compatible and dynamically castable back to the type of
 ///   the boxed value, but is otherwise opaque.
 ///
-/// TODO: This should subsume `_bridgeToObjectiveC` above.
 /// COMPILER_INTRINSIC
 public func _bridgeAnythingToObjectiveC<T>(_ x: T) -> AnyObject {
   if _fastPath(_isClassOrObjCExistential(T.self)) {
@@ -217,7 +165,6 @@ public func _bridgeAnythingToObjectiveC<T>(_ x: T) -> AnyObject {
   return _bridgeAnythingNonVerbatimToObjectiveC(x)
 }
 
-// TODO: This should subsume `_bridgeNonVerbatimToObjectiveC` above.
 /// COMPILER_INTRINSIC
 @_silgen_name("_swift_bridgeAnythingNonVerbatimToObjectiveC")
 public func _bridgeAnythingNonVerbatimToObjectiveC<T>(_ x: T) -> AnyObject
@@ -262,8 +209,6 @@ public func _forceBridgeFromObjectiveC_bridgeable<T:_ObjectiveCBridgeable> (
 ///   - if the dynamic type of `x` is `T` or a subclass of it, it is bridged
 ///     verbatim, the function returns `x`;
 /// - otherwise, if `T` conforms to `_ObjectiveCBridgeable`:
-///   + if `T._isBridgedToObjectiveC()` returns `false`, then the result is
-///     empty;
 ///   + otherwise, if the dynamic type of `x` is not `T._ObjectiveCType`
 ///     or a subclass of it, the result is empty;
 ///   + otherwise, returns the result of
@@ -319,8 +264,7 @@ func _bridgeNonVerbatimFromObjectiveCConditional<T>(
 /// representation.
 ///
 /// - If `T` is a class type, returns `true`;
-/// - otherwise, if `T` conforms to `_ObjectiveCBridgeable`, returns
-///   `T._isBridgedToObjectiveC()`.
+/// - otherwise, returns whether `T` conforms to `_ObjectiveCBridgeable`.
 public func _isBridgedToObjectiveC<T>(_: T.Type) -> Bool {
   if _fastPath(_isClassOrObjCExistential(T.self)) {
     return true

stdlib/public/core/ContiguousArrayBuffer.swift

@@ -145,7 +145,7 @@ final class _ContiguousArrayStorage<Element> : _ContiguousArrayStorage1 {
     let resultPtr = result.baseAddress
     let p = __manager._elementPointer
     for i in 0..<count {
-      (resultPtr + i).initialize(to: _bridgeToObjectiveCUnconditional(p[i]))
+      (resultPtr + i).initialize(to: _bridgeAnythingToObjectiveC(p[i]))
     }
     _fixLifetime(__manager)
     return result
@@ -428,9 +428,6 @@ struct _ContiguousArrayBuffer<Element> : _ArrayBufferProtocol {
   ///
   /// - Complexity: O(1).
   public func _asCocoaArray() -> _NSArrayCore {
-    _sanityCheck(
-        _isBridgedToObjectiveC(Element.self),
-        "Array element type is not bridged to Objective-C")
     if count == 0 {
       return _emptyArrayStorage
     }

stdlib/public/core/HashedCollections.swift.gyb

@@ -1184,7 +1184,7 @@ extension Set {
       var i = lhsNative.startIndex
       while i != endIndex {
         let key = lhsNative.assertingGet(i)
-        let bridgedKey: AnyObject = _bridgeToObjectiveCUnconditional(key)
+        let bridgedKey: AnyObject = _bridgeAnythingToObjectiveC(key)
         let optRhsValue: AnyObject? = rhsCocoa.maybeGet(bridgedKey)
         if let rhsValue = optRhsValue {
           if key == _forceBridgeFromObjectiveC(rhsValue, Element.self) {
@@ -1301,10 +1301,8 @@ public func _setBridgeToObjectiveC<SwiftValue, ObjCValue>(
     if valueBridgesDirectly {
       bridgedMember = unsafeBitCast(member, to: ObjCValue.self)
     } else {
-      let bridged: AnyObject? = _bridgeToObjectiveC(member)
-      _precondition(bridged != nil,
-      "set member cannot be bridged to Objective-C")
-      bridgedMember = unsafeBitCast(bridged!, to: ObjCValue.self)
+      let bridged: AnyObject = _bridgeAnythingToObjectiveC(member)
+      bridgedMember = unsafeBitCast(bridged, to: ObjCValue.self)
     }
     result.insert(bridgedMember)
   }
@@ -2109,7 +2107,7 @@ extension Dictionary where Key : Equatable, Value : Equatable {
       while index != endIndex {
         let (key, value) = lhsNative.assertingGet(index)
         let optRhsValue: AnyObject? =
-          rhsCocoa.maybeGet(_bridgeToObjectiveCUnconditional(key))
+          rhsCocoa.maybeGet(_bridgeAnythingToObjectiveC(key))
         // TODO: swift-3-indexing-model: change 'if' into 'guard'.
         if let rhsValue = optRhsValue {
           if value == _forceBridgeFromObjectiveC(rhsValue, Value.self) {
@@ -2245,9 +2243,8 @@ public func _dictionaryBridgeToObjectiveC<
     if keyBridgesDirectly {
       bridgedKey = unsafeBitCast(key, to: ObjCKey.self)
     } else {
-      let bridged: AnyObject? = _bridgeToObjectiveC(key)
-      _precondition(bridged != nil, "dictionary key cannot be bridged to Objective-C")
-      bridgedKey = unsafeBitCast(bridged!, to: ObjCKey.self)
+      let bridged: AnyObject = _bridgeAnythingToObjectiveC(key)
+      bridgedKey = unsafeBitCast(bridged, to: ObjCKey.self)
     }
 
     // Bridge the value
@@ -2255,10 +2252,8 @@ public func _dictionaryBridgeToObjectiveC<
     if valueBridgesDirectly {
       bridgedValue = unsafeBitCast(value, to: ObjCValue.self)
     } else {
-      let bridged: AnyObject? = _bridgeToObjectiveC(value)
-      _precondition(bridged != nil,
-          "dictionary value cannot be bridged to Objective-C")
-      bridgedValue = unsafeBitCast(bridged!, to: ObjCValue.self)
+      let bridged: AnyObject? = _bridgeAnythingToObjectiveC(value)
+      bridgedValue = unsafeBitCast(bridged, to: ObjCValue.self)
     }
 
     result[bridgedKey] = bridgedValue
@@ -3410,11 +3405,11 @@ final internal class _Native${Self}StorageOwner<${TypeParametersDecl}>
     // Bridge everything.
     for i in 0..<nativeStorage.capacity {
       if nativeStorage.isInitializedEntry(at: i) {
-        let key = _bridgeToObjectiveCUnconditional(nativeStorage.key(at: i))
+        let key = _bridgeAnythingToObjectiveC(nativeStorage.key(at: i))
 %if Self == 'Set':
         bridged.initializeKey(key, at: i)
 %elif Self == 'Dictionary':
-        let val = _bridgeToObjectiveCUnconditional(nativeStorage.value(at: i))
+        let val = _bridgeAnythingToObjectiveC(nativeStorage.value(at: i))
         bridged.initializeKey(key, value: val, at: i)
 %end
       }
@@ -3433,9 +3428,9 @@ final internal class _Native${Self}StorageOwner<${TypeParametersDecl}>
     AnyObject {
     if _fastPath(_isClassOrObjCExistential(Key.self)) {
 %if Self == 'Set':
-      return _bridgeToObjectiveCUnconditional(nativeStorage.assertingGet(i))
+      return _bridgeAnythingToObjectiveC(nativeStorage.assertingGet(i))
 %elif Self == 'Dictionary':
-      return _bridgeToObjectiveCUnconditional(nativeStorage.assertingGet(i).0)
+      return _bridgeAnythingToObjectiveC(nativeStorage.assertingGet(i).0)
 %end
     }
     bridgeEverything()
@@ -3451,7 +3446,7 @@ final internal class _Native${Self}StorageOwner<${TypeParametersDecl}>
   internal func _getBridgedValue(_ i: _Native${Self}Index<${TypeParameters}>) ->
     AnyObject {
     if _fastPath(_isClassOrObjCExistential(Value.self)) {
-      return _bridgeToObjectiveCUnconditional(nativeStorage.assertingGet(i))
+      return _bridgeAnythingToObjectiveC(nativeStorage.assertingGet(i))
     }
     bridgeEverything()
     return bridgedNativeStorage.assertingGet(i.offset)
@@ -3462,7 +3457,7 @@ final internal class _Native${Self}StorageOwner<${TypeParametersDecl}>
   internal func _getBridgedValue(_ i: _Native${Self}Index<${TypeParameters}>)
     -> AnyObject {
     if _fastPath(_isClassOrObjCExistential(Value.self)) {
-      return _bridgeToObjectiveCUnconditional(nativeStorage.assertingGet(i).1)
+      return _bridgeAnythingToObjectiveC(nativeStorage.assertingGet(i).1)
     }
     bridgeEverything()
     return bridgedNativeStorage.assertingGet(i.offset).1
@@ -3952,7 +3947,7 @@ internal enum _Variant${Self}Storage<${TypeParametersDecl}> : _HashStorage {
       return nil
     case .cocoa(let cocoaStorage):
 #if _runtime(_ObjC)
-      let anyObjectKey: AnyObject = _bridgeToObjectiveCUnconditional(key)
+      let anyObjectKey: AnyObject = _bridgeAnythingToObjectiveC(key)
       if let cocoaIndex = cocoaStorage.index(forKey: anyObjectKey) {
         return ._cocoa(cocoaIndex)
       }
@@ -4001,7 +3996,7 @@ internal enum _Variant${Self}Storage<${TypeParametersDecl}> : _HashStorage {
     case .cocoa(let cocoaStorage):
 #if _runtime(_ObjC)
       // FIXME: This assumes that Key and Value are bridged verbatim.
-      let anyObjectKey: AnyObject = _bridgeToObjectiveCUnconditional(key)
+      let anyObjectKey: AnyObject = _bridgeAnythingToObjectiveC(key)
       let anyObjectValue: AnyObject = cocoaStorage.assertingGet(anyObjectKey)
       return _forceBridgeFromObjectiveC(anyObjectValue, Value.self)
 #else
@@ -4016,7 +4011,7 @@ internal enum _Variant${Self}Storage<${TypeParametersDecl}> : _HashStorage {
   internal static func maybeGetFromCocoaStorage(
     _ cocoaStorage : CocoaStorage, forKey key: Key
   ) -> Value? {
-    let anyObjectKey: AnyObject = _bridgeToObjectiveCUnconditional(key)
+    let anyObjectKey: AnyObject = _bridgeAnythingToObjectiveC(key)
     if let anyObjectValue = cocoaStorage.maybeGet(anyObjectKey) {
       return _forceBridgeFromObjectiveC(anyObjectValue, Value.self)
     }
@@ -4322,7 +4317,7 @@ internal enum _Variant${Self}Storage<${TypeParametersDecl}> : _HashStorage {
       return nativeRemoveObject(forKey: key)
     case .cocoa(let cocoaStorage):
 #if _runtime(_ObjC)
-      let anyObjectKey: AnyObject = _bridgeToObjectiveCUnconditional(key)
+      let anyObjectKey: AnyObject = _bridgeAnythingToObjectiveC(key)
       if cocoaStorage.maybeGet(anyObjectKey) == nil {
         return nil
       }
@@ -5033,13 +5028,6 @@ extension ${Self} {
   public func _bridgeToObjectiveCImpl() -> _NS${Self}Core {
     switch _variantStorage {
     case _Variant${Self}Storage.native(let nativeOwner):
-%if Self == 'Set':
-      _precondition(_isBridgedToObjectiveC(Element.self),
-        "Key is not bridged to Objective-C")
-%elif Self == 'Dictionary':
-      _precondition(_isBridgedToObjectiveC(Value.self),
-        "Value is not bridged to Objective-C")
-%end
       return nativeOwner as _Native${Self}StorageOwner<${TypeParameters}>
 
     case _Variant${Self}Storage.cocoa(let cocoaStorage):

stdlib/public/core/ImplicitlyUnwrappedOptional.swift

@@ -71,7 +71,7 @@ extension ImplicitlyUnwrappedOptional : _ObjectiveCBridgeable {
       _preconditionFailure("attempt to bridge an implicitly unwrapped optional containing nil")
 
     case .some(let x):
-      return Swift._bridgeToObjectiveC(x)!
+      return Swift._bridgeAnythingToObjectiveC(x)
     }
   }
 

stdlib/public/core/NewtypeWrapper.swift.gyb

@@ -30,10 +30,6 @@ public func ${op} <T: _SwiftNewtypeWrapper>(lhs: T, rhs: T) -> Bool
 
 #if _runtime(_ObjC)
 extension _SwiftNewtypeWrapper where Self.RawValue : _ObjectiveCBridgeable {
-  public static func _isBridgedToObjectiveC() -> Bool {
-    return Self.RawValue._isBridgedToObjectiveC()
-  }
-
   public func _bridgeToObjectiveC() -> Self.RawValue._ObjectiveCType {
     return rawValue._bridgeToObjectiveC()
   }

stdlib/public/core/Reflection.swift

@@ -510,7 +510,7 @@ public func _swift_ClassMirror_quickLookObject(_: _MagicMirrorData) -> AnyObject
 func _swift_isKind(_ object: AnyObject, of: AnyObject) -> Bool
 
 func _isKind(_ object: AnyObject, of: String) -> Bool {
-  return _swift_isKind(object, of: _bridgeToObjectiveC(of)!)
+  return _swift_isKind(object, of: _bridgeAnythingToObjectiveC(of))
 }
 
 func _getClassPlaygroundQuickLook(_ object: AnyObject) -> PlaygroundQuickLook? {

stdlib/public/runtime/Casting.cpp

@@ -2516,11 +2516,6 @@ struct _ObjectiveCBridgeableWitnessTable {
                      const Metadata *parentMetadata,
                      const _ObjectiveCBridgeableWitnessTable *witnessTable);
 
-  // class func _isBridgedToObjectiveC() -> bool
-  bool (*isBridgedToObjectiveC)(
-         const Metadata *value, const Metadata *T,
-         const _ObjectiveCBridgeableWitnessTable *witnessTable);
-
   // func _bridgeToObjectiveC() -> _ObjectiveCType
   HeapObject *(*bridgeToObjectiveC)(
                 OpaqueValue *self, const Metadata *Self,
@@ -2561,12 +2556,6 @@ static bool _dynamicCastValueToClassViaObjCBridgeable(
                const Metadata *targetType,
                const _ObjectiveCBridgeableWitnessTable *srcBridgeWitness,
                DynamicCastFlags flags) {
-  // Check whether the source is bridged to Objective-C.
-  if (!srcBridgeWitness->isBridgedToObjectiveC(srcType, srcType,
-                                               srcBridgeWitness)) {
-    return _fail(src, srcType, targetType, flags);
-  }
-
   // Bridge the source value to an object.
   auto srcBridgedObject =
     srcBridgeWitness->bridgeToObjectiveC(src, srcType, srcBridgeWitness);
@@ -2604,12 +2593,6 @@ static bool _dynamicCastValueToClassExistentialViaObjCBridgeable(
               const ExistentialTypeMetadata *targetType,
               const _ObjectiveCBridgeableWitnessTable *srcBridgeWitness,
               DynamicCastFlags flags) {
-  // Check whether the source is bridged to Objective-C.
-  if (!srcBridgeWitness->isBridgedToObjectiveC(srcType, srcType,
-                                               srcBridgeWitness)) {
-    return _fail(src, srcType, targetType, flags);
-  }
-
   // Bridge the source value to an object.
   auto srcBridgedObject =
     srcBridgeWitness->bridgeToObjectiveC(src, srcType, srcBridgeWitness);
@@ -2646,12 +2629,6 @@ static bool _dynamicCastClassToValueViaObjCBridgeable(
                const Metadata *targetType,
                const _ObjectiveCBridgeableWitnessTable *targetBridgeWitness,
                DynamicCastFlags flags) {
-  // Check whether the target is bridged to Objective-C.
-  if (!targetBridgeWitness->isBridgedToObjectiveC(targetType, targetType,
-                                                  targetBridgeWitness)) {
-    return _fail(src, srcType, targetType, flags);
-  }
-
   // Determine the class type to which the target value type is bridged.
   auto targetBridgedClass =
     targetBridgeWitness->ObjectiveCType(targetType, targetBridgeWitness);
@@ -2772,12 +2749,6 @@ static id bridgeAnythingNonVerbatimToObjectiveC(OpaqueValue *src,
   }
   
   if (auto srcBridgeWitness = findBridgeWitness(srcType)) {
-    // Check whether the source is bridged to Objective-C.
-    if (!srcBridgeWitness->isBridgedToObjectiveC(srcType, srcType,
-                                                 srcBridgeWitness)) {
-      return nil;
-    }
-
     // Bridge the source value to an object.
     auto srcBridgedObject =
       srcBridgeWitness->bridgeToObjectiveC(src, srcType, srcBridgeWitness);
@@ -2850,30 +2821,6 @@ findBridgeWitness(const Metadata *T) {
   return nullptr;
 }
 
-/// \param value passed at +1, consumed.
-SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
-extern "C" HeapObject *_swift_bridgeNonVerbatimToObjectiveC(
-  OpaqueValue *value, const Metadata *T
-) {
-  assert(!swift_isClassOrObjCExistentialTypeImpl(T));
-
-  if (const auto *bridgeWitness = findBridgeWitness(T)) {
-    if (!bridgeWitness->isBridgedToObjectiveC(T, T, bridgeWitness)) {
-      // Witnesses take 'self' at +0, so we still need to consume the +1 argument.
-      T->vw_destroy(value);
-      return nullptr;
-    }
-    auto result = bridgeWitness->bridgeToObjectiveC(value, T, bridgeWitness);
-    // Witnesses take 'self' at +0, so we still need to consume the +1 argument.
-    T->vw_destroy(value);
-    return result;
-  }
-
-  // Consume the +1 argument.
-  T->vw_destroy(value);
-  return nullptr;
-}
-
 SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERFACE
 extern "C" const Metadata *_swift_getBridgedNonVerbatimObjectiveCType(
   const Metadata *value, const Metadata *T
@@ -2987,8 +2934,7 @@ extern "C" bool _swift_isBridgedNonVerbatimToObjectiveC(
   assert(!swift_isClassOrObjCExistentialTypeImpl(T));
 
   auto bridgeWitness = findBridgeWitness(T);
-  return bridgeWitness && bridgeWitness->isBridgedToObjectiveC(value, T,
-                                                               bridgeWitness);
+  return (bool)bridgeWitness;
 }
 #endif