Merge pull request #71298 from nate-chandler/bitwise-copyable/remove-unchecked

[BitwiseCopyable] Remove @unchecked behavior.

Author: nate-chandler

lib/SIL/IR/TypeLowering.cpp

@@ -28,7 +28,6 @@
 #include "swift/AST/Pattern.h"
 #include "swift/AST/PrettyStackTrace.h"
 #include "swift/AST/PropertyWrappers.h"
-#include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/TypeDifferenceVisitor.h"
 #include "swift/AST/Types.h"
 #include "swift/ClangImporter/ClangModule.h"
@@ -3010,21 +3009,6 @@ void TypeConverter::verifyLexicalLowering(const TypeLowering &lowering,
   }
 }
 
-static bool isUnchecked(ProtocolConformanceRef conformance) {
-  if (!conformance)
-    return false;
-  if (!conformance.isConcrete())
-    return false;
-  auto concrete = conformance.getConcrete();
-  assert(concrete);
-  auto *root = concrete->getRootConformance();
-  assert(root);
-  auto *normal = dyn_cast<NormalProtocolConformance>(root);
-  if (!normal)
-    return false;
-  return normal->isUnchecked();
-}
-
 void TypeConverter::verifyTrivialLowering(const TypeLowering &lowering,
                                           AbstractionPattern origType,
                                           CanType substType,
@@ -3058,17 +3042,10 @@ void TypeConverter::verifyTrivialLowering(const TypeLowering &lowering,
           if (!nominal)
             return false;
 
-          // Don't walk into types whose conformance is unchecked--such
-          // conformances obstruct automatic inference of BitwiseCopyable.
-          auto conformance = M.checkConformance(ty, bitwiseCopyableProtocol);
-          if (isUnchecked(conformance)) {
-            return true;
-          }
-
-          // Nominals with fields that conditionally conform to BitwiseCopyable
-          // must be explicitly conditionally conformed.  Such a field must be a
-          // generic context.
-          if (nominal->isGenericContext()) {
+          // Nominals with generic parameters must be explicitly conformed to
+          // BitwiseCopyable.
+          auto *generic = ty.getAnyGeneric();
+          if (generic && generic->isGenericContext()) {
             return true;
           }
 
@@ -3082,12 +3059,10 @@ void TypeConverter::verifyTrivialLowering(const TypeLowering &lowering,
           // Return false to indicate seeing a leaf which justifies the type
           // being trivial but not conforming to BitwiseCopyable.
 
-          // A BitwiseCopyable conformer appearing within its layout explains a
-          // non-conformance iff the conformance is @unchecked.
-          auto conformance = M.checkConformance(ty, bitwiseCopyableProtocol);
-          if (conformance) {
-            return !isUnchecked(conformance);
-          }
+          // A BitwiseCopyable conformer appearing within its layout doesn't
+          // explain why substType doesn't itself conform.
+          if (M.checkConformance(ty, bitwiseCopyableProtocol))
+            return true;
 
           // ModuleTypes are trivial but don't warrant being given a conformance
           // to BitwiseCopyable.
@@ -3124,15 +3099,15 @@ void TypeConverter::verifyTrivialLowering(const TypeLowering &lowering,
             return true;
           }
 
-          /// A field of conditionally-BitwiseCopyable type justifies the
-          /// aggregate not conforming because the aggregate must be conformed
-          /// explicitly in that case.
-          if (nominal->isGenericContext()) {
+          /// A non-conforming generic nominal type justifies substType not
+          /// conforming.
+          auto *generic = ty.getAnyGeneric();
+          if (generic && generic->isGenericContext()) {
             return false;
           }
 
           // The field is trivial and the whole type is nonconforming.  That's
-          // legal iff the field's type is public.
+          // legal iff the type is public.
           return !nominal
                       ->getFormalAccessScope(
                           /*useDC=*/nullptr,
@@ -3173,7 +3148,6 @@ void TypeConverter::verifyTrivialLowering(const TypeLowering &lowering,
       llvm::errs() << "Non-trivial type with _BitwiseCopyable conformance!?:\n"
                    << substType << "\n";
       conformance.print(llvm::errs());
-      llvm::errs() << "\n";
       assert(false);
     }
   }

lib/Sema/TypeCheckBitwise.cpp

@@ -106,7 +106,6 @@ class BitwiseCopyableStorageVisitor : public StorageVisitor {
 
   bool visitMemberDecl(ValueDecl *storage, Type ty);
   bool visitMemberType(Type type, SourceLoc loc);
-  bool isUnchecked(ProtocolConformanceRef conformance);
   bool visitNonconformingMemberType(Type type, SourceLoc loc);
   void emitNonconformingMemberTypeDiagnostic(Type ty, SourceLoc loc);
 };
@@ -137,13 +136,6 @@ bool BitwiseCopyableStorageVisitor::visitMemberType(Type ty, SourceLoc loc) {
     return visitNonconformingMemberType(ty, loc);
   }
 
-  if (isImplicit(check) && isUnchecked(conformance)) {
-    // Do not automatically derive conformance if one of the field's
-    // conformance is @unchecked.
-    invalid = true;
-    return true;
-  }
-
   // Walk the conformance, diagnosing any missing BitwiseCopyable conformances.
   bool anyMissing = false;
   conformance.forEachMissingConformance(
@@ -158,20 +150,6 @@ bool BitwiseCopyableStorageVisitor::visitMemberType(Type ty, SourceLoc loc) {
   return anyMissing;
 }
 
-bool BitwiseCopyableStorageVisitor::isUnchecked(
-    ProtocolConformanceRef conformance) {
-  if (!conformance.isConcrete())
-    return false;
-  auto concrete = conformance.getConcrete();
-  assert(concrete);
-  auto *root = concrete->getRootConformance();
-  assert(root);
-  auto *normal = dyn_cast<NormalProtocolConformance>(root);
-  if (!normal)
-    return false;
-  return normal->isUnchecked();
-}
-
 bool BitwiseCopyableStorageVisitor::visitNonconformingMemberType(
     Type ty, SourceLoc loc) {
   if (ty->hasError())

lib/Sema/TypeCheckProtocol.cpp

@@ -2165,8 +2165,7 @@ static void diagnoseConformanceImpliedByConditionalConformance(
 /// to the given protocol. This should return true when @unchecked can be
 /// used to disable those semantic checks.
 static bool hasAdditionalSemanticChecks(ProtocolDecl *proto) {
-  return proto->isSpecificProtocol(KnownProtocolKind::Sendable) ||
-         proto->isSpecificProtocol(KnownProtocolKind::BitwiseCopyable);
+  return proto->isSpecificProtocol(KnownProtocolKind::Sendable);
 }
 
 /// Determine whether the type \c T conforms to the protocol \c Proto,

stdlib/public/core/BridgeObjectiveC.swift

@@ -407,7 +407,7 @@ public func _getBridgedNonVerbatimObjectiveCType<T>(_: T.Type) -> Any.Type?
 /// already have writeback-scoped lifetime.
 @frozen
 public struct AutoreleasingUnsafeMutablePointer<Pointee /* TODO : class */>
-  :  _Pointer, @unchecked _BitwiseCopyable {
+  :  _Pointer {
 
   public let _rawValue: Builtin.RawPointer
 

stdlib/public/core/CTypes.swift

@@ -142,7 +142,7 @@ public typealias CBool = Bool
 /// Opaque pointers are used to represent C pointers to types that
 /// cannot be represented in Swift, such as incomplete struct types.
 @frozen
-public struct OpaquePointer : @unchecked _BitwiseCopyable {
+public struct OpaquePointer {
   @usableFromInline
   internal var _rawValue: Builtin.RawPointer
 

stdlib/public/core/UnsafeBufferPointer.swift.gyb

@@ -30,8 +30,7 @@
 /// collection with an `${Self}` instance copies the instances out of the
 /// referenced memory and into the new collection.
 @frozen // unsafe-performance
-public struct Unsafe${Mutable}BufferPointer<Element> 
-  : @unchecked _BitwiseCopyable {
+public struct Unsafe${Mutable}BufferPointer<Element> {
 
   @usableFromInline
   let _position: Unsafe${Mutable}Pointer<Element>?

stdlib/public/core/UnsafePointer.swift

@@ -205,7 +205,7 @@
 ///       let numberPointer = UnsafePointer<Int>(&number)
 ///       // Accessing 'numberPointer' is undefined behavior.
 @frozen // unsafe-performance
-public struct UnsafePointer<Pointee>: _Pointer, @unchecked _BitwiseCopyable {
+public struct UnsafePointer<Pointee>: _Pointer {
 
   /// A type that represents the distance between two pointers.
   public typealias Distance = Int
@@ -578,8 +578,7 @@ public struct UnsafePointer<Pointee>: _Pointer, @unchecked _BitwiseCopyable {
 ///       let numberPointer = UnsafeMutablePointer<Int>(&number)
 ///       // Accessing 'numberPointer' is undefined behavior.
 @frozen // unsafe-performance
-public struct UnsafeMutablePointer<Pointee>
-  : _Pointer, @unchecked _BitwiseCopyable {
+public struct UnsafeMutablePointer<Pointee>: _Pointer {
 
   /// A type that represents the distance between two pointers.
   public typealias Distance = Int

stdlib/public/core/UnsafeRawPointer.swift

@@ -169,7 +169,7 @@
 ///       let numberPointer = UnsafeRawPointer(&number)
 ///       // Accessing 'numberPointer' is undefined behavior.
 @frozen
-public struct UnsafeRawPointer: _Pointer, @unchecked _BitwiseCopyable {
+public struct UnsafeRawPointer: _Pointer {
 
   public typealias Pointee = UInt8
 
@@ -727,7 +727,7 @@ extension UnsafeRawPointer {
 ///       let numberPointer = UnsafeMutableRawPointer(&number)
 ///       // Accessing 'numberPointer' is undefined behavior.
 @frozen
-public struct UnsafeMutableRawPointer: _Pointer, @unchecked _BitwiseCopyable {
+public struct UnsafeMutableRawPointer: _Pointer {
 
   public typealias Pointee = UInt8
 

test/Sema/bitwise_copyable.swift

@@ -96,21 +96,6 @@ struct S_Explicit_With_Metatype_Optional_AnyObject : _BitwiseCopyable {
   var ty: Optional<AnyObject>.Type
 }
 
-struct S_Unchecked : @unchecked _BitwiseCopyable {}
-
-struct S_Implicit_With_S_Unchecked {
-  var s: S_Unchecked
-}
-
-func passS_Implicit_With_S_Unchecked(_ s: S_Implicit_With_S_Unchecked) {
-  take1(s) // expected-error{{type_does_not_conform_decl_owner}}
-           // expected-note@-92 {{where_requirement_failure_one_subst}}
-}
-
-struct S_Explicit_With_S_Unchecked : _BitwiseCopyable {
-  var s: S_Unchecked
-}
-
 //==============================================================================
 //===========================DEPENDENCY-FREE TESTS=(END)======================}}
 //==============================================================================

test/SourceKit/DocSupport/doc_clang_module.swift.response

@@ -5654,11 +5654,6 @@ var FooSubUnnamedEnumeratorA1: Int { get }
         key.kind: source.lang.swift.ref.protocol,
         key.name: "_Pointer",
         key.usr: "s:s8_PointerP"
-      },
-      {
-        key.kind: source.lang.swift.ref.protocol,
-        key.name: "_BitwiseCopyable",
-        key.usr: "s:s16_BitwiseCopyableP"
       }
     ]
   },