Reinstate generalization of Optional.unsafelyUnwrapped

Author: lorentey

stdlib/public/core/Optional.swift

@@ -320,7 +320,7 @@ extension Optional where Wrapped: ~Copyable {
   }
 }
 
-extension Optional {
+extension Optional where Wrapped: ~Escapable {
   /// The wrapped value of this instance, unwrapped without checking whether
   /// the instance is `nil`.
   ///
@@ -345,12 +345,14 @@ extension Optional {
   ///   will never be equal to `nil` and only after you've tried using the
   ///   postfix `!` operator.
   @inlinable
+  @_preInverseGenerics
   @unsafe
   public var unsafelyUnwrapped: Wrapped {
-    // FIXME: Generalize this for ~Escapable wrapped types. Unfortunately this
-    // currently hides it from C++ interop, breaking the stdlib overlay.
-    // (rdar://145800780)
+    // FIXME: Generalize this for ~Copyable wrapped types. Note that the current
+    // implementation is copying the value, so that generalization will need to
+    // be emitted into clients -- `@_preInverseGenerics` will not cut it.
     @inline(__always)
+    @lifetime(copy self)
     get {
       if let x = self {
         return x

test/Interop/CxxToSwiftToCxx/bridge-cxx-enum-back-to-cxx-execution.cpp

@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies
+// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies -enable-experimental-feature LifetimeDependence
 // RUN: %target-swift-frontend -typecheck %t/use-cxx-types.swift -typecheck -module-name UseCxx -emit-clang-header-path %t/UseCxx.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public
 
 // RUN: %target-interop-build-clangxx -std=c++20 -c %t/use-swift-cxx-types.cpp -I %t -o %t/swift-cxx-execution.o -g
@@ -11,6 +11,7 @@
 // RUN: %target-run %t/swift-cxx-execution
 
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_LifetimeDependence
 
 //--- header.h
 enum class SomeEnum {

test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx-execution.cpp

@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies
+// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies -enable-experimental-feature LifetimeDependence
 
 // RUN: %target-swift-frontend -typecheck %t/use-cxx-types.swift -typecheck -module-name UseCxx -emit-clang-header-path %t/UseCxx.h -I %t -enable-experimental-cxx-interop -clang-header-expose-decls=all-public
 
@@ -12,6 +12,7 @@
 // RUN: %target-run %t/swift-cxx-execution | %FileCheck %s
 
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_LifetimeDependence
 
 //--- header.h
 

test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift

@@ -1,10 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr-or-stdlib -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies
+// RUN: %target-swift-frontend -parse-as-library %platform-module-dir/Swift.swiftmodule/%module-target-triple.swiftinterface -enable-library-evolution -disable-objc-attr-requires-foundation-module -typecheck -module-name Swift -parse-stdlib -enable-experimental-cxx-interop -clang-header-expose-decls=has-expose-attr-or-stdlib -emit-clang-header-path %t/Swift.h  -experimental-skip-all-function-bodies -enable-experimental-feature LifetimeDependence
 // RUN: %FileCheck %s < %t/Swift.h
 
 // RUN: %check-interop-cxx-header-in-clang(%t/Swift.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -Wno-unused-private-field -Wno-unused-function -Wc++98-compat-extra-semi)
 // RUN: %check-interop-cxx-header-in-clang(%t/Swift.h -DSWIFT_CXX_INTEROP_HIDE_STL_OVERLAY -Wno-unused-private-field -Wno-unused-function -Wc++98-compat-extra-semi -DDEBUG=1)
 
+// REQUIRES: swift_feature_LifetimeDependence
+
 // CHECK: namespace swift SWIFT_PRIVATE_ATTR SWIFT_SYMBOL_MODULE("swift") {
 
 // CHECK: template<class T_0_0>

test/api-digester/Outputs/stability-stdlib-source-base.swift.expected

@@ -367,6 +367,7 @@ Struct CollectionOfOne is now with @_addressableForDependencies
 Protocol CodingKey has added inherited protocol SendableMetatype
 Protocol Error has added inherited protocol SendableMetatype
 
+Accessor Optional.unsafelyUnwrapped.Get() has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Escapable>
 Accessor UnsafeBufferPointer.indices.Get() has generic signature change from <Element> to <Element where Element : ~Copyable>
 Accessor UnsafeMutableBufferPointer.indices.Get() has generic signature change from <Element> to <Element where Element : ~Copyable>
 

test/api-digester/stability-stdlib-abi-without-asserts.test

@@ -837,6 +837,10 @@ Struct EnumeratedSequence has added a conformance to an existing protocol Bidire
 Struct EnumeratedSequence has added a conformance to an existing protocol Collection
 Struct EnumeratedSequence has added a conformance to an existing protocol RandomAccessCollection
 
+Accessor Optional.unsafelyUnwrapped.Get() has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Escapable>
+Accessor Optional.unsafelyUnwrapped.Get() has mangled name changing from 'Swift.Optional.unsafelyUnwrapped.getter : A' to '(extension in Swift):Swift.Optional< where A: ~Swift.Escapable>.unsafelyUnwrapped.getter : A'
+Var Optional.unsafelyUnwrapped has mangled name changing from 'Swift.Optional.unsafelyUnwrapped : A' to '(extension in Swift):Swift.Optional< where A: ~Swift.Escapable>.unsafelyUnwrapped : A'
+Var Optional.unsafelyUnwrapped is now with @_preInverseGenerics
 Accessor Optional._unsafelyUnwrappedUnchecked.Get() has generic signature change from <Wrapped> to <Wrapped where Wrapped : ~Escapable>
 Accessor Optional._unsafelyUnwrappedUnchecked.Get() has mangled name changing from 'Swift.Optional._unsafelyUnwrappedUnchecked.getter : A' to '(extension in Swift):Swift.Optional< where A: ~Swift.Escapable>._unsafelyUnwrappedUnchecked.getter : A'
 Var Optional._unsafelyUnwrappedUnchecked has mangled name changing from 'Swift.Optional._unsafelyUnwrappedUnchecked : A' to '(extension in Swift):Swift.Optional< where A: ~Swift.Escapable>._unsafelyUnwrappedUnchecked : A'