AST: Re-baseline MemorySafetyAttributes feature.

Author: tshortli

include/swift/Basic/Features.def

@@ -254,8 +254,8 @@ CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) fu
 LANGUAGE_FEATURE(IsolatedAny2, 431, "@isolated(any) function types")
 LANGUAGE_FEATURE(ObjCImplementation, 436, "@objc @implementation extensions")
 LANGUAGE_FEATURE(NonescapableTypes, 446, "Nonescapable types")
-SUPPRESSIBLE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
 BASELINE_LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
+BASELINE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
 BASELINE_LANGUAGE_FEATURE(ValueGenerics, 452, "Value generics feature (integer generics)")
 LANGUAGE_FEATURE(RawIdentifiers, 451, "Raw identifiers")
 LANGUAGE_FEATURE(SendableCompletionHandlers, 463, "Objective-C completion handler parameters are imported as @Sendable")

lib/AST/ASTPrinter.cpp

@@ -3280,20 +3280,6 @@ struct ExcludeAttrRAII {
 };
 }
 
-static void
-suppressingFeatureMemorySafetyAttributes(PrintOptions &options,
-                                       llvm::function_ref<void()> action) {
-  ExcludeAttrRAII scope(options.ExcludeAttrList, DeclAttrKind::Unsafe);
-  ExcludeAttrRAII scope2(options.ExcludeAttrList, DeclAttrKind::Safe);
-  options.ExcludeAttrList.push_back(TypeAttrKind::Unsafe);
-  SWIFT_DEFER {
-    assert(options.ExcludeAttrList.back() == TypeAttrKind::Unsafe);
-    options.ExcludeAttrList.pop_back();
-  };
-
-  action();
-}
-
 static void
 suppressingFeatureCoroutineAccessors(PrintOptions &options,
                                      llvm::function_ref<void()> action) {

lib/AST/FeatureSet.cpp

@@ -451,35 +451,6 @@ static bool usesFeatureCDecl(Decl *decl) {
   return attr && !attr->Underscored;
 }
 
-static bool usesFeatureMemorySafetyAttributes(Decl *decl) {
-  if (decl->getAttrs().hasAttribute<SafeAttr>() ||
-      decl->getAttrs().hasAttribute<UnsafeAttr>())
-    return true;
-
-  IterableDeclContext *idc;
-  if (auto nominal = dyn_cast<NominalTypeDecl>(decl))
-    idc = nominal;
-  else if (auto ext = dyn_cast<ExtensionDecl>(decl))
-    idc = ext;
-  else
-    idc = nullptr;
-
-  // Look for an @unsafe conformance ascribed to this declaration.
-  if (idc) {
-    auto conformances = idc->getLocalConformances();
-    for (auto conformance : conformances) {
-      auto rootConformance = conformance->getRootConformance();
-      if (auto rootNormalConformance =
-              dyn_cast<NormalProtocolConformance>(rootConformance)) {
-        if (rootNormalConformance->getExplicitSafety() == ExplicitSafety::Unsafe)
-          return true;
-      }
-    }
-  }
-
-  return false;
-}
-
 UNINTERESTING_FEATURE(StrictMemorySafety)
 UNINTERESTING_FEATURE(SafeInteropWrappers)
 UNINTERESTING_FEATURE(AssumeResilientCxxTypes)

test/Unsafe/interface_printing.swift

@@ -2,11 +2,7 @@
 // RUN: %target-swift-typecheck-module-from-interface(%t.swiftinterface) -module-name UserModule
 // RUN: %FileCheck %s < %t.swiftinterface
 
-// CHECK: #if compiler(>=5.3) && $MemorySafetyAttributes
 // CHECK: @unsafe public func getIntUnsafely() -> Swift.Int
-// CHECK: #else
-// CHECK: public func getIntUnsafely() -> Swift.Int
-// CHECK: #endif
 @unsafe public func getIntUnsafely() -> Int { 0 }
 
 public struct UnsafeIterator: @unsafe IteratorProtocol {
@@ -33,13 +29,8 @@ public protocol P {
   func f()
 }
 
-// CHECK:  #if compiler(>=5.3) && $MemorySafetyAttributes
 // CHECK: public struct X : @unsafe UserModule.P
 public struct X: @unsafe P {
 // CHECK:  @unsafe public func f()
-// CHECK:  #else
-// CHECK: public struct X : UserModule.P
-// CHECK:  public func f()
-// CHECK:  #endif
   @unsafe public func f() { }
 }