Enable @objc @implementation (SE-0436) as an ordinary language feature

include/swift/AST/DiagnosticsSema.def

@@ -1767,16 +1767,16 @@ ERROR(attr_objc_implementation_must_be_unconditional,none,
       "only unconditional extensions can implement an Objective-C '@interface'",
       ())
 ERROR(attr_objc_implementation_must_be_imported,none,
-      "'@_objcImplementation' cannot be used to extend %kind0 because it was "
+      "'@objc @implementation' cannot be used to extend %kind0 because it was "
       "defined by a Swift 'class' declaration, not an imported Objective-C "
       "'@interface' declaration",
       (ValueDecl *))
 ERROR(attr_objc_implementation_must_have_super,none,
-      "'@_objcImplementation' cannot be used to implement root %kind0; declare "
-      "its superclass in the header",
+      "'@objc @implementation' cannot be used to implement root %kind0; "
+      "declare its superclass in the header",
       (ValueDecl *))
 ERROR(objc_implementation_cannot_have_generics,none,
-      "'@_objcImplementation' cannot be used to implement %kind0",
+      "'@objc @implementation' cannot be used to implement %kind0",
       (ValueDecl *))
 ERROR(attr_objc_implementation_category_not_found,none,
       "could not find category %0 on Objective-C class %1; make sure your "
@@ -1794,7 +1794,7 @@ ERROR(attr_objc_implementation_no_category_for_func,none,
       "name from this attribute",
       (ValueDecl*))
 ERROR(attr_objc_implementation_no_conformance,none,
-      "'@_objcImplementation' extension cannot add conformance to %0; "
+      "'@objc @implementation' extension cannot add conformance to %0; "
       "add this conformance %select{with an ordinary extension|"
       "in the Objective-C header}1",
       (Type, bool))
@@ -1922,7 +1922,7 @@ NOTE(objc_implementation_requirement_here,none,
      (ValueDecl *))
 
 ERROR(objc_implementation_init_must_be_convenience, none,
-      "%kind0 is not valid in an '@_objcImplementation' extension because "
+      "%kind0 is not valid in an '@objc @implementation' extension because "
       "Objective-C subclasses must be able to override "
       "%select{designated|required}1 initializers",
       (const ValueDecl *, /*isRequired=*/bool))
@@ -1936,7 +1936,7 @@ NOTE(objc_implementation_init_turn_required_to_convenience, none,
 
 // Fallback diagnostic; super-general by nature.
 ERROR(objc_implementation_member_requires_vtable, none,
-      "%kind0 is not valid in an '@_objcImplementation' extension because it "
+      "%kind0 is not valid in an '@objc @implementation' extension because it "
       "is an overridable Swift-only %kindonly0",
       (const ValueDecl *))
 

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.swift

@@ -13,8 +13,8 @@ protocol EmptySwiftProto {}
   // FIXME: give better diagnostic expected-error@-4 {{extension for main class interface should provide implementation for property 'propertyFromHeader8'}}
   // FIXME: give better diagnostic expected-error@-5 {{extension for main class interface should provide implementation for property 'propertyFromHeader7'}}
   // FIXME: give better diagnostic expected-error@-6 {{extension for main class interface should provide implementation for instance method 'method(fromHeader3:)'}}
-  // expected-error@-7 {{'@_objcImplementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
-  // expected-error@-8 {{'@_objcImplementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
+  // expected-error@-7 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
+  // expected-error@-8 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
   // expected-error@-9 {{extension for main class interface should provide implementation for instance method 'extensionMethod(fromHeader2:)'}}
 
   func method(fromHeader1: CInt) {
@@ -207,12 +207,12 @@ protocol EmptySwiftProto {}
   }
 
   @nonobjc public init(notFromHeader4: CInt) {
-    // expected-error@-1 {{initializer 'init(notFromHeader4:)' is not valid in an '@_objcImplementation' extension because Objective-C subclasses must be able to override designated initializers}}
+    // expected-error@-1 {{initializer 'init(notFromHeader4:)' is not valid in an '@objc @implementation' extension because Objective-C subclasses must be able to override designated initializers}}
     // expected-note@-2 {{add 'convenience' keyword to make this a convenience initializer}} {{12-12=convenience }}
   }
 
   @nonobjc public required init(notFromHeader5: CInt) {
-    // expected-error@-1 {{initializer 'init(notFromHeader5:)' is not valid in an '@_objcImplementation' extension because Objective-C subclasses must be able to override required initializers}}
+    // expected-error@-1 {{initializer 'init(notFromHeader5:)' is not valid in an '@objc @implementation' extension because Objective-C subclasses must be able to override required initializers}}
     // expected-note@-2 {{replace 'required' keyword with 'convenience' to make this a convenience initializer}} {{19-27=convenience}}
   }
 
@@ -478,17 +478,17 @@ protocol EmptySwiftProto {}
 // expected-note@-1 2 {{'SwiftClass' declared here}}
 
 @objc @implementation extension SwiftClass {}
-// expected-error@-1 {{'@_objcImplementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{7-23=}}
+// expected-error@-1 {{'@objc @implementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{7-23=}}
 
 @objc(WTF) @implementation extension SwiftClass {} // expected
-// expected-error@-1 {{'@_objcImplementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{12-28=}}
+// expected-error@-1 {{'@objc @implementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{12-28=}}
 
 @objc @implementation extension ObjCImplRootClass {
-  // expected-error@-1 {{'@_objcImplementation' cannot be used to implement root class 'ObjCImplRootClass'; declare its superclass in the header}}
+  // expected-error@-1 {{'@objc @implementation' cannot be used to implement root class 'ObjCImplRootClass'; declare its superclass in the header}}
 }
 
 @objc @implementation extension ObjCImplGenericClass {
-  // expected-error@-1 {{'@_objcImplementation' cannot be used to implement generic class 'ObjCImplGenericClass'}}
+  // expected-error@-1 {{'@objc @implementation' cannot be used to implement generic class 'ObjCImplGenericClass'}}
 }
 
 @implementation extension ObjCBadClass {

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_early_adopter.swift

@@ -10,8 +10,8 @@ protocol EmptySwiftProto {}
   // FIXME: give better diagnostic expected-warning@-4 {{extension for main class interface should provide implementation for property 'propertyFromHeader8'}}
   // FIXME: give better diagnostic expected-warning@-5 {{extension for main class interface should provide implementation for property 'propertyFromHeader7'}}
   // FIXME: give better diagnostic expected-warning@-6 {{extension for main class interface should provide implementation for instance method 'method(fromHeader3:)'}}
-  // expected-warning@-7 {{'@_objcImplementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
-  // expected-warning@-8 {{'@_objcImplementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
+  // expected-warning@-7 {{'@objc @implementation' extension cannot add conformance to 'EmptySwiftProto'; add this conformance with an ordinary extension}}
+  // expected-warning@-8 {{'@objc @implementation' extension cannot add conformance to 'EmptyObjCProto'; add this conformance in the Objective-C header}}
   // expected-warning@-9 {{extension for main class interface should provide implementation for instance method 'extensionMethod(fromHeader2:)'}}
 
   func method(fromHeader1: CInt) {
@@ -204,12 +204,12 @@ protocol EmptySwiftProto {}
   }
 
   @nonobjc public init(notFromHeader4: CInt) {
-    // expected-warning@-1 {{initializer 'init(notFromHeader4:)' is not valid in an '@_objcImplementation' extension because Objective-C subclasses must be able to override designated initializers}}
+    // expected-warning@-1 {{initializer 'init(notFromHeader4:)' is not valid in an '@objc @implementation' extension because Objective-C subclasses must be able to override designated initializers}}
     // expected-note@-2 {{add 'convenience' keyword to make this a convenience initializer}} {{12-12=convenience }}
   }
 
   @nonobjc public required init(notFromHeader5: CInt) {
-    // expected-warning@-1 {{initializer 'init(notFromHeader5:)' is not valid in an '@_objcImplementation' extension because Objective-C subclasses must be able to override required initializers}}
+    // expected-warning@-1 {{initializer 'init(notFromHeader5:)' is not valid in an '@objc @implementation' extension because Objective-C subclasses must be able to override required initializers}}
     // expected-note@-2 {{replace 'required' keyword with 'convenience' to make this a convenience initializer}} {{19-27=convenience}}
   }
 
@@ -477,17 +477,17 @@ protocol EmptySwiftProto {}
 // expected-note@-1 2 {{'SwiftClass' declared here}}
 
 @_objcImplementation extension SwiftClass {}
-// expected-error@-1 {{'@_objcImplementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{1-22=}}
+// expected-error@-1 {{'@objc @implementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{1-22=}}
 
 @_objcImplementation(WTF) extension SwiftClass {} // expected
-// expected-error@-1 {{'@_objcImplementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{1-27=}}
+// expected-error@-1 {{'@objc @implementation' cannot be used to extend class 'SwiftClass' because it was defined by a Swift 'class' declaration, not an imported Objective-C '@interface' declaration}} {{1-27=}}
 
 @_objcImplementation extension ObjCImplRootClass {
-  // expected-error@-1 {{'@_objcImplementation' cannot be used to implement root class 'ObjCImplRootClass'; declare its superclass in the header}}
+  // expected-error@-1 {{'@objc @implementation' cannot be used to implement root class 'ObjCImplRootClass'; declare its superclass in the header}}
 }
 
 @_objcImplementation extension ObjCImplGenericClass {
-  // expected-error@-1 {{'@_objcImplementation' cannot be used to implement generic class 'ObjCImplGenericClass'}}
+  // expected-error@-1 {{'@objc @implementation' cannot be used to implement generic class 'ObjCImplGenericClass'}}
 }
 
 //

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
   }