[stdlib] _BridgeStorage: Remove second type parameter (ObjCClass)

It used to be a shadow protocol existential, but now it’s invariably AnyObject.
I see no reason to keep supporting this unused abstraction.

Author: lorentey

Diff for: stdlib/public/core/ArrayBuffer.swift

@@ -20,7 +20,7 @@ import SwiftShims
 
 @usableFromInline
 internal typealias _ArrayBridgeStorage
-  = _BridgeStorage<__ContiguousArrayStorageBase, AnyObject>
+  = _BridgeStorage<__ContiguousArrayStorageBase>
 
 @usableFromInline
 @_fixed_layout

Diff for: stdlib/public/core/BridgeStorage.swift

@@ -13,7 +13,7 @@
 //  Types that are bridged to Objective-C need to manage an object
 //  that may be either some native class or the @objc Cocoa
 //  equivalent.  _BridgeStorage discriminates between these two
-//  possibilities and stores a few extra bits when the stored type is
+//  possibilities and stores a single extra bit when the stored type is
 //  native.  It is assumed that the @objc class instance may in fact
 //  be a tagged pointer, and thus no extra bits may be available.
 //
@@ -22,15 +22,12 @@ import SwiftShims
 
 @_fixed_layout
 @usableFromInline
-internal struct _BridgeStorage<
-  NativeClass: AnyObject,
-  ObjCClass: AnyObject
-> {
+internal struct _BridgeStorage<NativeClass: AnyObject> {
   @usableFromInline
   internal typealias Native = NativeClass
 
   @usableFromInline
-  internal typealias ObjC = ObjCClass
+  internal typealias ObjC = AnyObject
 
   // rawValue is passed inout to _isUnique.  Although its value
   // is unchanged, it must appear mutable to the optimizer.

Diff for: stdlib/public/core/DictionaryVariant.swift

@@ -35,7 +35,7 @@ extension Dictionary {
   @_fixed_layout
   internal struct _Variant {
     @usableFromInline
-    internal var object: _BridgeStorage<_RawDictionaryStorage, AnyObject>
+    internal var object: _BridgeStorage<_RawDictionaryStorage>
 
     @inlinable
     @inline(__always)

Diff for: stdlib/public/core/SetVariant.swift

@@ -31,7 +31,7 @@ extension Set {
   @_fixed_layout
   internal struct _Variant {
     @usableFromInline
-    internal var object: _BridgeStorage<_RawSetStorage, AnyObject>
+    internal var object: _BridgeStorage<_RawSetStorage>
 
     @inlinable
     @inline(__always)

Diff for: test/SILOptimizer/dead_array_elim.sil

@@ -64,7 +64,7 @@ bb0(%0 : $TrivialDestructor):
   store %0 to %10 : $*TrivialDestructor
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   strong_retain %0 : $TrivialDestructor
   strong_release %15 : $Builtin.BridgeObject
 // CHECK-NEXT: tuple ()
@@ -91,7 +91,7 @@ bb0(%0 : $TrivialDestructor):
   %7 = pointer_to_address %6 : $Builtin.RawPointer to [strict] $*TrivialDestructor
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   strong_retain %0 : $TrivialDestructor
   strong_release %15 : $Builtin.BridgeObject
 
@@ -121,7 +121,7 @@ bb0(%0 : $TrivialDestructor):
   %6 = tuple_extract %4 : $(Array<TrivialDestructor>, Builtin.RawPointer), 1
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   cond_br undef, bb1, bb2
 
 bb1:
@@ -159,7 +159,7 @@ bb1:
   %5 = tuple_extract %4 : $(Array<TrivialDestructor>, Builtin.RawPointer), 0
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   strong_release %15 : $Builtin.BridgeObject
   %18 = tuple ()
   return %18 : $()
@@ -190,7 +190,7 @@ bb0(%0 : $TrivialDestructor):
   %12 = tuple_extract %4 : $(Array<TrivialDestructor>, Builtin.RawPointer), 0
   %13 = struct_extract %12 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   strong_release %15 : $Builtin.BridgeObject
 
   return %22 : $TrivialDestructor
@@ -217,7 +217,7 @@ bb0(%0 : $TrivialDestructor, %1 : $TrivialDestructor):
   %7 = pointer_to_address %6 : $Builtin.RawPointer to [strict] $*TrivialDestructor
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   cond_br undef, bb1, bb2
 
 bb1:
@@ -260,7 +260,7 @@ bb1:
   %7 = pointer_to_address %6 : $Builtin.RawPointer to [strict] $*TrivialDestructor
   %13 = struct_extract %5 : $Array<TrivialDestructor>, #Array._buffer
   %14 = struct_extract %13 : $_ArrayBuffer<TrivialDestructor>, #_ArrayBuffer._storage
-  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %15 = struct_extract %14 : $_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   strong_retain %0 : $TrivialDestructor
   store %0 to %7 : $*TrivialDestructor
   strong_release %15 : $Builtin.BridgeObject

Diff for: test/SILOptimizer/licm_multiend.sil

@@ -55,7 +55,7 @@ bb0:
   %1 = struct_element_addr %0 : $*ReversedCollection<Array<Int>>, #ReversedCollection._base
   %2 = struct_element_addr %1 : $*Array<Int>, #Array._buffer
   %3 = struct_element_addr %2 : $*_ArrayBuffer<Int>, #_ArrayBuffer._storage
-  %4 = struct_element_addr %3 : $*_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %4 = struct_element_addr %3 : $*_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   %5 = load %4 : $*Builtin.BridgeObject
   %6 = unchecked_ref_cast %5 : $Builtin.BridgeObject to $__ContiguousArrayStorageBase
   %7 = ref_element_addr %6 : $__ContiguousArrayStorageBase, #__ContiguousArrayStorageBase.countAndCapacity
@@ -140,7 +140,7 @@ bb0:
   %1 = struct_element_addr %0 : $*ReversedCollection<Array<Int>>, #ReversedCollection._base
   %2 = struct_element_addr %1 : $*Array<Int>, #Array._buffer
   %3 = struct_element_addr %2 : $*_ArrayBuffer<Int>, #_ArrayBuffer._storage
-  %4 = struct_element_addr %3 : $*_BridgeStorage<__ContiguousArrayStorageBase, AnyObject>, #_BridgeStorage.rawValue
+  %4 = struct_element_addr %3 : $*_BridgeStorage<__ContiguousArrayStorageBase>, #_BridgeStorage.rawValue
   %5 = load %4 : $*Builtin.BridgeObject
   %6 = unchecked_ref_cast %5 : $Builtin.BridgeObject to $__ContiguousArrayStorageBase
   %7 = ref_element_addr %6 : $__ContiguousArrayStorageBase, #__ContiguousArrayStorageBase.countAndCapacity

Diff for: test/api-digester/Outputs/stability-stdlib-abi.swift.expected

@@ -289,7 +289,7 @@ Func Dictionary._bridgeToObjectiveCImpl() has return type change from _NSDiction
 Func _NativeDictionary.bridged() has return type change from _NSDictionary to AnyObject
 Protocol _NSDictionary has been removed
 Protocol _NSDictionaryCore has been removed
-Var Dictionary._Variant.object has declared type change from _BridgeStorage<_RawDictionaryStorage, _NSDictionary> to _BridgeStorage<_RawDictionaryStorage, AnyObject>
+Var Dictionary._Variant.object has declared type change from _BridgeStorage<_RawDictionaryStorage, _NSDictionary> to _BridgeStorage<_RawDictionaryStorage>
 Var _CocoaDictionary.object has declared type change from _NSDictionary to AnyObject
 
 Class _EmptySetSingleton has removed conformance to _NSSetCore
@@ -301,7 +301,7 @@ Func _NativeSet.bridged() has return type change from _NSSet to AnyObject
 Func _stdlib_CFSetGetValues(_:_:) has been removed
 Protocol _NSSet has been removed
 Protocol _NSSetCore has been removed
-Var Set._Variant.object has declared type change from _BridgeStorage<_RawSetStorage, _NSSet> to _BridgeStorage<_RawSetStorage, AnyObject>
+Var Set._Variant.object has declared type change from _BridgeStorage<_RawSetStorage, _NSSet> to _BridgeStorage<_RawSetStorage>
 Var _CocoaSet.object has declared type change from _NSSet to AnyObject
 
 Protocol _NSNumber has been removed
@@ -313,7 +313,7 @@ Class __SwiftDeferredNSArray has removed conformance to _NSArrayCore
 Class __SwiftNativeNSArrayWithContiguousStorage has removed conformance to _NSArrayCore
 Constructor Array.init(_immutableCocoaArray:) has parameter 0 type change from _NSArrayCore to AnyObject
 Constructor _ArrayBuffer.init(nsArray:) has parameter 0 type change from _NSArrayCore to AnyObject
-Constructor _ArrayBuffer.init(storage:) has parameter 0 type change from _BridgeStorage<__ContiguousArrayStorageBase, _NSArrayCore> to _BridgeStorage<__ContiguousArrayStorageBase, AnyObject>
+Constructor _ArrayBuffer.init(storage:) has parameter 0 type change from _BridgeStorage<__ContiguousArrayStorageBase, _NSArrayCore> to _BridgeStorage<__ContiguousArrayStorageBase>
 Constructor _CocoaArrayWrapper.init(_:) has parameter 0 type change from _NSArrayCore to AnyObject
 Func _ArrayBuffer._asCocoaArray() has return type change from _NSArrayCore to AnyObject
 Func _CocoaArrayWrapper.contiguousStorage(_:) has been removed
@@ -325,8 +325,22 @@ Struct _CocoaArrayWrapper has type witness type for Collection.SubSequence chang
 Struct _CocoaArrayWrapper has type witness type for RandomAccessCollection.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
 Struct _CocoaArrayWrapper has type witness type for Sequence.SubSequence changing from Slice<_CocoaArrayWrapper> to _SliceBuffer<AnyObject>
 Var _ArrayBuffer._nonNative has declared type change from _NSArrayCore to _CocoaArrayWrapper
-Var _ArrayBuffer._storage has declared type change from _BridgeStorage<__ContiguousArrayStorageBase, _NSArrayCore> to _BridgeStorage<__ContiguousArrayStorageBase, AnyObject>
+Var _ArrayBuffer._storage has declared type change from _BridgeStorage<__ContiguousArrayStorageBase, _NSArrayCore> to _BridgeStorage<__ContiguousArrayStorageBase>
 Var _CocoaArrayWrapper.buffer has declared type change from _NSArrayCore to AnyObject
 
 Var _SliceBuffer.endIndexAndFlags in a non-resilient type changes position from 2 to 3
 Var _SliceBuffer.startIndex in a non-resilient type changes position from 3 to 2
+
+Constructor _BridgeStorage.init(native:) has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Constructor _BridgeStorage.init(native:) has return type change from _BridgeStorage<τ_0_0, τ_0_1> to _BridgeStorage<τ_0_0>
+Constructor _BridgeStorage.init(native:isFlagged:) has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Constructor _BridgeStorage.init(native:isFlagged:) has return type change from _BridgeStorage<τ_0_0, τ_0_1> to _BridgeStorage<τ_0_0>
+Constructor _BridgeStorage.init(objC:) has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Constructor _BridgeStorage.init(objC:) has parameter 0 type change from τ_0_1 to AnyObject
+Constructor _BridgeStorage.init(objC:) has return type change from _BridgeStorage<τ_0_0, τ_0_1> to _BridgeStorage<τ_0_0>
+Constructor _BridgeStorage.init(taggedPayload:) has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Constructor _BridgeStorage.init(taggedPayload:) has return type change from _BridgeStorage<τ_0_0, τ_0_1> to _BridgeStorage<τ_0_0>
+Func _BridgeStorage.isUniquelyReferencedNative() has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Func _BridgeStorage.isUniquelyReferencedUnflaggedNative() has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Struct _BridgeStorage has generic signature change from <τ_0_0, τ_0_1 where τ_0_0 : AnyObject, τ_0_1 : AnyObject> to <τ_0_0 where τ_0_0 : AnyObject>
+Var _BridgeStorage.objCInstance has declared type change from τ_0_1 to AnyObject

Diff for: test/stdlib/BridgeStorage.swift

@@ -116,10 +116,10 @@ var unTaggedNSString : NSString {
 }
 
 allTests.test("_BridgeStorage") {
-  typealias B = _BridgeStorage<C, NSString>
+  typealias B = _BridgeStorage<C>
 
   let oy: NSString = "oy"
-  expectTrue(B(objC: oy).objCInstance == oy)
+  expectTrue(B(objC: oy).objCInstance === oy)
 
   for flag in [false, true] {
     do {