[Set/Dictionary] Eliminate "bridging" collection entrypoints.

Remove the functions
_(set|dictionary)Bridge(From|To)ObjectiveC(Conditional) from the
standard library. These entrypoints are no longer used by the compiler
(thanks to generalized collection up/downcasting), so stop using them
in Foundation and in tests.

Author: DougGregor

stdlib/public/SDK/Foundation/Foundation.swift

@@ -638,13 +638,7 @@ extension Dictionary : _ObjectiveCBridgeable {
     result: inout Dictionary?
   ) -> Bool {
     let anyDict = x as [NSObject : AnyObject]
-    if _isBridgedVerbatimToObjectiveC(Key.self) &&
-       _isBridgedVerbatimToObjectiveC(Value.self) {
-      result = Swift._dictionaryDownCastConditional(anyDict)
-      return result != nil
-    }
-
-    result = Swift._dictionaryBridgeFromObjectiveCConditional(anyDict)
+    result = Swift._dictionaryDownCastConditional(anyDict)
     return result != nil
   }
 
@@ -888,12 +882,7 @@ extension Set : _ObjectiveCBridgeable {
     _ x: NSSet, result: inout Set?
   ) -> Bool {
     let anySet = x as Set<NSObject>
-    if _isBridgedVerbatimToObjectiveC(Element.self) {
-      result = Swift._setDownCastConditional(anySet)
-      return result != nil
-    }
-
-    result = Swift._setBridgeFromObjectiveCConditional(anySet)
+    result = Swift._setDownCastConditional(anySet)
     return result != nil
   }
 

stdlib/public/core/HashedCollections.swift.gyb

@@ -1291,40 +1291,6 @@ public func _setUpCast<DerivedValue, BaseValue>(_ source: Set<DerivedValue>)
   return builder.take()
 }
 
-#if _runtime(_ObjC)
-
-/// Implements an unconditional upcast that involves bridging.
-///
-/// The cast can fail if bridging fails.
-///
-/// - Precondition: `SwiftValue` is bridged to Objective-C
-///   and requires non-trivial bridging.
-public func _setBridgeToObjectiveC<SwiftValue, ObjCValue>(
-  _ source: Set<SwiftValue>
-) -> Set<ObjCValue> {
-  _sanityCheck(_isClassOrObjCExistential(ObjCValue.self))
-  _sanityCheck(!_isBridgedVerbatimToObjectiveC(SwiftValue.self))
-
-  var result = Set<ObjCValue>(minimumCapacity: source.count)
-  let valueBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftValue.self) ==
-    _isBridgedVerbatimToObjectiveC(ObjCValue.self)
-
-  for member in source {
-    var bridgedMember: ObjCValue
-    if valueBridgesDirectly {
-      bridgedMember = unsafeBitCast(member, to: ObjCValue.self)
-    } else {
-      let bridged: AnyObject = _bridgeAnythingToObjectiveC(member)
-      bridgedMember = unsafeBitCast(bridged, to: ObjCValue.self)
-    }
-    result.insert(bridgedMember)
-  }
-  return result
-}
-
-#endif
-
 @_silgen_name("_swift_setDownCastIndirect")
 public func _setDownCastIndirect<SourceValue, TargetValue>(
   _ source: UnsafePointer<Set<SourceValue>>,
@@ -1389,64 +1355,6 @@ public func _setDownCastConditional<BaseValue, DerivedValue>(
     })
 }
 
-#if _runtime(_ObjC)
-
-/// Implements an unconditional downcast that involves bridging.
-///
-/// - Precondition: At least one of `SwiftValue` is a bridged value
-///   type, and the corresponding `ObjCValue` is a reference type.
-public func _setBridgeFromObjectiveC<ObjCValue, SwiftValue>(
-  _ source: Set<ObjCValue>
-) -> Set<SwiftValue> {
-  let result: Set<SwiftValue>? = _setBridgeFromObjectiveCConditional(source)
-  _precondition(result != nil, "This set cannot be bridged from Objective-C")
-  return result!
-}
-
-/// Implements a conditional downcast that involves bridging.
-///
-/// If the cast fails, the function returns `nil`.  All checks should be
-/// performed eagerly.
-///
-/// - Precondition: At least one of `SwiftValue` is a bridged value
-///   type, and the corresponding `ObjCValue` is a reference type.
-public func _setBridgeFromObjectiveCConditional<
-  ObjCValue, SwiftValue
->(
-  _ source: Set<ObjCValue>
-) -> Set<SwiftValue>? {
-  _sanityCheck(_isClassOrObjCExistential(ObjCValue.self))
-  _sanityCheck(!_isBridgedVerbatimToObjectiveC(SwiftValue.self))
-
-  let valueBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftValue.self) ==
-      _isBridgedVerbatimToObjectiveC(ObjCValue.self)
-
-  var result = Set<SwiftValue>(minimumCapacity: source.count)
-  for value in source {
-    // Downcast the value.
-    var resultValue: SwiftValue
-    if valueBridgesDirectly {
-      if let bridgedValue = value as? SwiftValue {
-        resultValue = bridgedValue
-      } else {
-        return nil
-      }
-    } else {
-      if let bridgedValue = _conditionallyBridgeFromObjectiveC(
-          _reinterpretCastToAnyObject(value), SwiftValue.self) {
-        resultValue = bridgedValue
-      } else {
-        return nil
-      }
-    }
-    result.insert(resultValue)
-  }
-  return result
-}
-
-#endif
-
 //===--- APIs unique to Dictionary<Key, Value> ----------------------------===//
 
 /// A collection whose elements are key-value pairs.
@@ -2216,66 +2124,6 @@ public func _dictionaryUpCast<DerivedKey, DerivedValue, BaseKey, BaseValue>(
   return result
 }
 
-#if _runtime(_ObjC)
-
-/// Implements an unconditional upcast that involves bridging.
-///
-/// The cast can fail if bridging fails.
-///
-/// - Precondition: `SwiftKey` and `SwiftValue` are bridged to Objective-C,
-///   and at least one of them requires non-trivial bridging.
-@inline(never)
-@_semantics("stdlib_binary_only")
-public func _dictionaryBridgeToObjectiveC<
-  SwiftKey, SwiftValue, ObjCKey, ObjCValue
->(
-  _ source: Dictionary<SwiftKey, SwiftValue>
-) -> Dictionary<ObjCKey, ObjCValue> {
-
-  // Note: We force this function to stay in the swift dylib because
-  // it is not performance sensitive and keeping it in the dylib saves
-  // a new kilobytes for each specialization for all users of dictionary.
-
-  _sanityCheck(
-    !_isBridgedVerbatimToObjectiveC(SwiftKey.self) ||
-    !_isBridgedVerbatimToObjectiveC(SwiftValue.self))
-  _sanityCheck(
-    _isClassOrObjCExistential(ObjCKey.self) ||
-    _isClassOrObjCExistential(ObjCValue.self))
-
-  var result = Dictionary<ObjCKey, ObjCValue>(minimumCapacity: source.count)
-  let keyBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftKey.self) ==
-      _isBridgedVerbatimToObjectiveC(ObjCKey.self)
-  let valueBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftValue.self) ==
-      _isBridgedVerbatimToObjectiveC(ObjCValue.self)
-  for (key, value) in source {
-    // Bridge the key
-    var bridgedKey: ObjCKey
-    if keyBridgesDirectly {
-      bridgedKey = unsafeBitCast(key, to: ObjCKey.self)
-    } else {
-      let bridged: AnyObject = _bridgeAnythingToObjectiveC(key)
-      bridgedKey = unsafeBitCast(bridged, to: ObjCKey.self)
-    }
-
-    // Bridge the value
-    var bridgedValue: ObjCValue
-    if valueBridgesDirectly {
-      bridgedValue = unsafeBitCast(value, to: ObjCValue.self)
-    } else {
-      let bridged: AnyObject? = _bridgeAnythingToObjectiveC(value)
-      bridgedValue = unsafeBitCast(bridged, to: ObjCValue.self)
-    }
-
-    result[bridgedKey] = bridgedValue
-  }
-
-  return result
-}
-#endif
-
 @_silgen_name("_swift_dictionaryDownCastIndirect")
 public func _dictionaryDownCastIndirect<SourceKey, SourceValue,
                                         TargetKey, TargetValue>(
@@ -2364,89 +2212,6 @@ public func _dictionaryDownCastConditional<
   return result
 }
 
-#if _runtime(_ObjC)
-/// Implements an unconditional downcast that involves bridging.
-///
-/// - Precondition: At least one of `SwiftKey` or `SwiftValue` is a bridged value
-///   type, and the corresponding `ObjCKey` or `ObjCValue` is a reference type.
-public func _dictionaryBridgeFromObjectiveC<
-  ObjCKey, ObjCValue, SwiftKey, SwiftValue
->(
-  _ source: Dictionary<ObjCKey, ObjCValue>
-) -> Dictionary<SwiftKey, SwiftValue> {
-  let result: Dictionary<SwiftKey, SwiftValue>? =
-    _dictionaryBridgeFromObjectiveCConditional(source)
-  _precondition(result != nil, "dictionary cannot be bridged from Objective-C")
-  return result!
-}
-
-/// Implements a conditional downcast that involves bridging.
-///
-/// If the cast fails, the function returns `nil`.  All checks should be
-/// performed eagerly.
-///
-/// - Precondition: At least one of `SwiftKey` or `SwiftValue` is a bridged value
-///   type, and the corresponding `ObjCKey` or `ObjCValue` is a reference type.
-public func _dictionaryBridgeFromObjectiveCConditional<
-  ObjCKey, ObjCValue, SwiftKey, SwiftValue
->(
-  _ source: Dictionary<ObjCKey, ObjCValue>
-) -> Dictionary<SwiftKey, SwiftValue>? {
-  _sanityCheck(
-    _isClassOrObjCExistential(ObjCKey.self) ||
-    _isClassOrObjCExistential(ObjCValue.self))
-  _sanityCheck(
-    !_isBridgedVerbatimToObjectiveC(SwiftKey.self) ||
-    !_isBridgedVerbatimToObjectiveC(SwiftValue.self))
-
-  let keyBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftKey.self) ==
-      _isBridgedVerbatimToObjectiveC(ObjCKey.self)
-  let valueBridgesDirectly =
-    _isBridgedVerbatimToObjectiveC(SwiftValue.self) ==
-      _isBridgedVerbatimToObjectiveC(ObjCValue.self)
-
-  var result = Dictionary<SwiftKey, SwiftValue>(minimumCapacity: source.count)
-  for (key, value) in source {
-    // Downcast the key.
-    var resultKey: SwiftKey
-    if keyBridgesDirectly {
-      if let bridgedKey = key as? SwiftKey {
-        resultKey = bridgedKey
-      } else {
-        return nil
-      }
-    } else {
-      if let bridgedKey = _conditionallyBridgeFromObjectiveC(
-        _reinterpretCastToAnyObject(key), SwiftKey.self) {
-          resultKey = bridgedKey
-      } else {
-        return nil
-      }
-    }
-
-    // Downcast the value.
-    var resultValue: SwiftValue
-    if valueBridgesDirectly {
-      if let bridgedValue = value as? SwiftValue {
-        resultValue = bridgedValue
-      } else {
-        return nil
-      }
-    } else {
-      if let bridgedValue = _conditionallyBridgeFromObjectiveC(
-        _reinterpretCastToAnyObject(value), SwiftValue.self) {
-          resultValue = bridgedValue
-      } else {
-        return nil
-      }
-    }
-
-    result[resultKey] = resultValue
-  }
-  return result
-}
-#endif
 //===--- APIs templated for Dictionary and Set ----------------------------===//
 
 %{

test/1_stdlib/DictionaryTrapsObjC.swift

@@ -144,7 +144,7 @@ DictionaryTraps.test("BridgedKeyIsNotNSCopyable2")
 DictionaryTraps.test("Downcast1") {
   let d: Dictionary<NSObject, NSObject> = [ TestObjCKeyTy(10): NSObject(),
                                             NSObject() : NSObject() ]
-  let d2: Dictionary<TestObjCKeyTy, NSObject> = _dictionaryDownCast(d)
+  let d2: Dictionary<TestObjCKeyTy, NSObject> = d as! Dictionary<TestObjCKeyTy, NSObject>
   expectCrashLater()
   let v1 = d2[TestObjCKeyTy(10)]
   let v2 = d2[TestObjCKeyTy(20)]
@@ -163,7 +163,7 @@ DictionaryTraps.test("Downcast2")
 
   expectCrashLater()
   let d2: Dictionary<TestBridgedKeyTy, NSObject>
-    = _dictionaryBridgeFromObjectiveC(d)
+    = d as! Dictionary<TestBridgedKeyTy, NSObject>
   let v1 = d2[TestBridgedKeyTy(10)]
 }
 

test/1_stdlib/SetTrapsObjC.swift

@@ -134,7 +134,7 @@ SetTraps.test("Downcast1")
     reason: "this trap is not guaranteed to happen in -Ounchecked"))
   .code {
   let s: Set<NSObject> = [ NSObject(), NSObject() ]
-  let s2: Set<TestObjCKeyTy> = _setDownCast(s)
+  let s2: Set<TestObjCKeyTy> = s as! Set<TestObjCKeyTy>
   expectCrashLater()
   let v1 = s2.contains(TestObjCKeyTy(10))
   let v2 = s2.contains(TestObjCKeyTy(20))
@@ -150,7 +150,7 @@ SetTraps.test("Downcast2")
   .code {
   let s: Set<NSObject> = [ TestObjCKeyTy(10), NSObject() ]
   expectCrashLater()
-  let s2: Set<TestBridgedKeyTy> = _setBridgeFromObjectiveC(s)
+  let s2: Set<TestBridgedKeyTy> = s as! Set<TestBridgedKeyTy>
   let v1 = s2.contains(TestBridgedKeyTy(10))
 }