Enable @objc @implementation feature

Author: beccadax

include/swift/Basic/Features.def

@@ -201,6 +201,7 @@ SUPPRESSIBLE_LANGUAGE_FEATURE(SendingArgsAndResults, 430, "Sending arg and resul
 LANGUAGE_FEATURE(BorrowingSwitch, 432, "Noncopyable type pattern matching")
 CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) function types")
 LANGUAGE_FEATURE(IsolatedAny2, 431, "@isolated(any) function types")
+LANGUAGE_FEATURE(ObjCImplementation, 436, "@objc @implementation extensions")
 
 // Swift 6
 UPCOMING_FEATURE(ConciseMagicFile, 274, 6)
@@ -378,9 +379,6 @@ EXPERIMENTAL_FEATURE(ClosureIsolation, true)
 // Whether lookup of members respects the enclosing file's imports.
 EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE(MemberImportVisibility, true)
 
-// Enable @implementation on extensions of ObjC classes.
-EXPERIMENTAL_FEATURE(ObjCImplementation, true)
-
 // Enable @implementation on extensions of ObjC classes with non-fixed layout
 // due to resilient stored properties. Requires OS support; this flag exists for
 // staging purposes.

test/IRGen/objc_implementation_deployment_target_resilience.swift

@@ -2,7 +2,7 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -target %target-stable-abi-triple -I %S/Inputs/abi -F %clang-importer-sdk-path/frameworks %s -import-objc-header %S/Inputs/objc_implementation.h -emit-ir -o %t.ir -enable-library-evolution -enable-experimental-feature ObjCImplementationWithResilientStorage -target %target-future-triple
 // REQUIRES: objc_interop
 
-@_objcImplementation extension ImplClassWithResilientStoredProperty {
+@objc @implementation extension ImplClassWithResilientStoredProperty {
   @objc var beforeInt: Int32 = 0    // no-error
   final var a: Mirror?              // expected-error {{does not support stored properties whose size can change due to library evolution; store this value in an object or 'any' type}}
   final var b: AnyKeyPath?          // no-error

test/decl/ext/objc_implementation_conflicts.swift

@@ -11,7 +11,7 @@
 import objc_implementation_private
 #endif
 
-@_objcImplementation extension ObjCClass {
+@objc @implementation extension ObjCClass {
   @objc func method(fromHeader1: CInt) {
     // OK, provides an implementation for the header's method.
   }
@@ -179,7 +179,7 @@ import objc_implementation_private
   let rdar122280735: (@escaping () -> ()) -> Void = { _ in }
 }
 
-@_objcImplementation(PresentAdditions) extension ObjCClass {
+@objc(PresentAdditions) @implementation extension ObjCClass {
   @objc func categoryMethod(fromHeader3: CInt) {
     // OK
   }

test/decl/ext/objc_implementation_features.swift

@@ -1,17 +1,14 @@
 // REQUIRES: objc_interop
 
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck %s -import-objc-header %S/Inputs/objc_implementation.h 2>&1 | %FileCheck --check-prefixes NO,CHECK %s
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck %s -import-objc-header %S/Inputs/objc_implementation.h -enable-experimental-feature ObjCImplementation 2>&1 | %FileCheck --check-prefixes YES,CHECK %s
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource) -typecheck %s -import-objc-header %S/Inputs/objc_implementation.h 2>&1 | %FileCheck %s
 
-// NO-NOT: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
-// YES-DAG: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
+// CHECK-DAG: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
 @_objcImplementation(EmptyCategory) extension ObjCClass {}
 
 // CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: warning: extension for main class interface should provide implementation for instance method 'subclassMethod(fromHeader1:)'; this will become an error after adopting '@implementation'
 // CHECK-NOT: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: warning: '@_objcImplementation' is deprecated; use '@implementation' instead
 @_objcImplementation extension ObjCSubclass {}
 
-// CHECK-DAG: objc_implementation_features.swift:[[@LINE+3]]:{{[0-9]+}}: error: extension for main class interface should provide implementation for initializer 'init()'{{$}}
-// NO-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: error: 'implementation' attribute is only valid when experimental feature ObjCImplementation is enabled
-// YES-NOT: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: error: 'implementation' attribute is only valid when experimental feature ObjCImplementation is enabled
+// CHECK-DAG: objc_implementation_features.swift:[[@LINE+2]]:{{[0-9]+}}: error: extension for main class interface should provide implementation for initializer 'init()'{{$}}
+// CHECK-NOT: objc_implementation_features.swift:[[@LINE+1]]:{{[0-9]+}}: error: 'implementation' attribute is only valid when experimental feature ObjCImplementation is enabled
 @objc @implementation extension ObjCBasicInitClass {}

test/decl/ext/objc_implementation_impl_only.swift

@@ -3,7 +3,7 @@
 
 @_implementationOnly import objc_implementation_internal
 
-@_objcImplementation extension InternalObjCClass {
+@objc @implementation extension InternalObjCClass {
   @objc public func method(fromHeader1: CInt) {
     // OK
   }