Merge branch 'release/5.6' into QuietMisdreavus/5.6/display-decl-recur

Author: franklinsch

CHANGELOG.md

@@ -6,6 +6,129 @@ _**Note:** This is in reverse chronological order, so newer entries are added to
 Swift 5.6
 ---------
 
+* Actor isolation checking now understands that `defer` bodies share the isolation of their enclosing function.
+
+  ```swift
+  // Works on global actors
+  @MainActor
+  func runAnimation(controller: MyViewController) async {
+    controller.hasActiveAnimation = true
+    defer { controller.hasActiveAnimation = false }
+
+    // do the animation here...
+  }
+
+  // Works on actor instances
+  actor OperationCounter {
+    var activeOperationCount = 0
+
+    func operate() async {
+      activeOperationCount += 1
+      defer { activeOperationCount -= 1 }
+
+      // do work here...
+    }
+  }
+  ```
+
+* [SE-0335][]:
+
+  Swift now allows existential types to be explicitly written with the `any`
+  keyword, creating a syntactic distinction between existential types and
+  protocol conformance constraints. For example:
+
+  ```swift
+  protocol P {}
+
+  func generic<T>(value: T) where T: P {
+    ...
+  }
+
+  func existential(value: any P) {
+     ...
+  }
+  ```
+
+* [SE-0337][]:
+
+  Swift now provides an incremental migration path to data race safety, allowing
+  APIs to adopt concurrency without breaking their clients that themselves have
+  not adopted concurrency. An existing declaration can introduce
+  concurrency-related annotations (such as making its closure parameters
+  `@Sendable`) and use the `@preconcurrency` attribute to maintain its behavior
+  for clients who have not themselves adopted concurrency:
+
+  ```swift
+  // module A
+  @preconcurrency func runOnSeparateTask(_ workItem: @Sendable () -> Void)
+
+  // module B
+  import A
+
+  class MyCounter {
+    var value = 0
+  }
+
+  func doesNotUseConcurrency(counter: MyCounter) {
+    runOnSeparateTask {
+      counter.value += 1 // no warning, because this code hasn't adopted concurrency
+    }
+  }
+
+  func usesConcurrency(counter: MyCounter) async {
+    runOnSeparateTask {
+      counter.value += 1 // warning: capture of non-Sendable type 'MyCounter'
+    }
+  }
+  ```
+
+  One can enable warnings about data race safety within a module with the
+  `-warn-concurrency` compiler option. When using a module that does not yet
+  provide `Sendable` annotations, one can suppress warnings for types from that
+  module by marking the import with `@preconcurrency`:
+
+  ```swift
+  /// module C
+  public struct Point {
+    public var x, y: Double
+  }
+
+  // module D
+  @preconcurrency import C
+
+  func centerView(at location: Point) {
+    Task {
+      await mainView.center(at: location) // no warning about non-Sendable 'Point' because the @preconcurrency import suppresses it
+    }
+  }
+  ```
+
+* [SE-0302][]:
+
+  Swift will now produce warnings to indicate potential data races when
+  non-`Sendable` types are passed across actor or task boundaries. For
+  example:
+
+  ```swift
+  class MyCounter {
+    var value = 0
+  }
+
+  func f() -> MyCounter {
+    let counter = MyCounter()
+    Task {
+      counter.value += 1  // warning: capture of non-Sendable type 'MyCounter'
+    }
+    return counter
+  }
+  ```
+
+* [SE-0331][]:
+
+  The conformance of the unsafe pointer types (e.g., `UnsafePointer`,
+  `UnsafeMutableBufferPointer`) to the `Sendable` protocols has been removed,
+  because pointers cannot safely be transferred across task or actor boundaries.
+
 * References to `Self` or so-called "`Self` requirements" in the type signatures
   of protocol members are now correctly detected in the parent of a nested type.
   As a result, protocol members that fall under this overlooked case are no longer
@@ -26,7 +149,7 @@ Swift 5.6
     // protocol type (use a generic constraint instead).
     _ = p.method
   }
-  ``` 
+  ```
 
 * [SE-0324][]:
 
@@ -53,6 +176,13 @@ Swift 5.6
   }
   ```
 
+* [SE-0322][]:
+
+  The standard library now provides a new operation
+  `withUnsafeTemporaryAllocation` which provides an efficient temporarily
+  allocation within a limited scope, which will be optimized to use stack
+  allocation when possible.
+
 * [SE-0315][]:
 
   Type expressions and annotations can now include "type placeholders" which
@@ -8753,14 +8883,19 @@ Swift 1.0
 [SE-0298]: <https://github.com/apple/swift-evolution/blob/main/proposals/0298-asyncsequence.md>
 [SE-0299]: <https://github.com/apple/swift-evolution/blob/main/proposals/0299-extend-generic-static-member-lookup.md>
 [SE-0300]: <https://github.com/apple/swift-evolution/blob/main/proposals/0300-continuation.md>
+[SE-0302]: <https://github.com/apple/swift-evolution/blob/main/proposals/0302-concurrent-value-and-concurrent-closures.md>
 [SE-0306]: <https://github.com/apple/swift-evolution/blob/main/proposals/0306-actors.md>
 [SE-0310]: <https://github.com/apple/swift-evolution/blob/main/proposals/0310-effectful-readonly-properties.md>
 [SE-0311]: <https://github.com/apple/swift-evolution/blob/main/proposals/0311-task-locals.md>
 [SE-0313]: <https://github.com/apple/swift-evolution/blob/main/proposals/0313-actor-isolation-control.md>
 [SE-0315]: <https://github.com/apple/swift-evolution/blob/main/proposals/0315-placeholder-types.md>
 [SE-0316]: <https://github.com/apple/swift-evolution/blob/main/proposals/0316-global-actors.md>
+[SE-0322]: <https://github.com/apple/swift-evolution/blob/main/proposals/0322-temporary-buffers.md>
 [SE-0324]: <https://github.com/apple/swift-evolution/blob/main/proposals/0324-c-lang-pointer-arg-conversion.md>
 [SE-0323]: <https://github.com/apple/swift-evolution/blob/main/proposals/0323-async-main-semantics.md>
+[SE-0331]: <https://github.com/apple/swift-evolution/blob/main/proposals/0331-remove-sendable-from-unsafepointer.md>
+[SE-0337]: <https://github.com/apple/swift-evolution/blob/main/proposals/0337-support-incremental-migration-to-concurrency-checking.md>
+[SE-0335]: <https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md>
 
 [SR-75]: <https://bugs.swift.org/browse/SR-75>
 [SR-106]: <https://bugs.swift.org/browse/SR-106>

docs/ABI/Mangling.rst

@@ -619,7 +619,7 @@ Types
   type-list ::= empty-list
 
                                                   // FIXME: Consider replacing 'h' with a two-char code
-  list-type ::= type identifier? 'Yk'? 'z'? 'h'? 'n'? 'Yi'? 'd'?  // type with optional label, '@noDerivative', inout convention, shared convention, owned convention, actor 'isolated', and variadic specifier
+  list-type ::= type identifier? 'Yk'? 'z'? 'h'? 'n'? 'Yi'? 'd'? 'Yt'?  // type with optional label, '@noDerivative', inout convention, shared convention, owned convention, actor 'isolated', variadic specifier, and compile-time constant
 
   METATYPE-REPR ::= 't'                      // Thin metatype representation
   METATYPE-REPR ::= 'T'                      // Thick metatype representation

include/swift/AST/ASTMangler.h

@@ -70,7 +70,7 @@ class ASTMangler : public Mangler {
   /// Whether the mangling predates concurrency, and therefore shouldn't
   /// include concurrency features such as global actors or @Sendable
   /// function types.
-  bool PredatesConcurrency = false;
+  bool Preconcurrency = false;
 
 public:
   using SymbolicReferent = llvm::PointerUnion<const NominalTypeDecl *,

include/swift/AST/Attr.def

@@ -688,9 +688,9 @@ SIMPLE_DECL_ATTR(_noAllocation, NoAllocation,
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   124)
 
-SIMPLE_DECL_ATTR(_predatesConcurrency, PredatesConcurrency,
+SIMPLE_DECL_ATTR(preconcurrency, Preconcurrency,
   OnFunc | OnConstructor | OnProtocol | OnGenericType | OnVar | OnSubscript |
-  OnEnumElement | OnImport | UserInaccessible |
+  OnEnumElement | OnImport |
   ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove,
   125)
 

include/swift/AST/Decl.h

@@ -896,7 +896,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   void setHoisted(bool hoisted = true) { Bits.Decl.Hoisted = hoisted; }
 
   /// Whether this declaration predates the introduction of concurrency.
-  bool predatesConcurrency() const;
+  bool preconcurrency() const;
 
 public:
   bool escapedFromIfConfig() const {

include/swift/AST/DeclContext.h

@@ -73,6 +73,7 @@ namespace swift {
   class PrefixOperatorDecl;
   class ProtocolConformance;
   class ValueDecl;
+  class VarDecl;
   class Initializer;
   class ClassDecl;
   class SerializedAbstractClosureExpr;
@@ -355,6 +356,11 @@ class alignas(1 << DeclContextAlignInBits) DeclContext
   LLVM_READONLY
   ProtocolDecl *getExtendedProtocolDecl() const;
 
+  /// If this DeclContext is the initializer expression of a global or instance
+  /// property, return the VarDecl, otherwise return null.
+  LLVM_READONLY
+  VarDecl *getNonLocalVarDecl() const;
+
   /// Retrieve the generic parameter 'Self' from a protocol or
   /// protocol extension.
   ///

include/swift/AST/DiagnosticsParse.def

@@ -1732,7 +1732,7 @@ ERROR(sil_inst_autodiff_invalid_witness_generic_signature,PointsToFirstBadToken,
       (StringRef, StringRef))
 
 WARNING(warn_attr_unsafe_removed,none,
-        "'%0' attribute has been removed in favor of @_predatesConcurrency",
+        "'%0' attribute has been removed in favor of @preconcurrency",
         (StringRef))
 
 //------------------------------------------------------------------------------

include/swift/AST/DiagnosticsSema.def

@@ -1953,11 +1953,11 @@ NOTE(add_nominal_sendable_conformance,none,
      "consider making %0 %1 conform to the 'Sendable' protocol",
      (DescriptiveDeclKind, DeclName))
 REMARK(add_predates_concurrency_import,none,
-     "add '@_predatesConcurrency' to %select{suppress|treat}0 "
+     "add '@preconcurrency' to %select{suppress|treat}0 "
      "'Sendable'-related %select{warnings|errors}0 from module %1"
      "%select{| as warnings}0", (bool, Identifier))
 REMARK(remove_predates_concurrency_import,none,
-     "'@_predatesConcurrency' attribute on module %0 is unused", (Identifier))
+     "'@preconcurrency' attribute on module %0 is unused", (Identifier))
 WARNING(public_decl_needs_sendable,none,
         "public %0 %1 does not specify whether it is 'Sendable' or not",
         (DescriptiveDeclKind, DeclName))
@@ -4475,6 +4475,10 @@ ERROR(global_actor_from_nonactor_context,none,
       "%0 %1 isolated to global actor %2 can not be %select{referenced|mutated|used 'inout'}4"
       " from %select{this|a non-isolated}3%select{| synchronous}5 context",
       (DescriptiveDeclKind, DeclName, Type, bool, unsigned, bool))
+ERROR(global_actor_from_initializing_expr,none,
+      "expression requiring global actor %0 cannot appear in "
+        "default-value expression of %1 %2",
+      (Type, DescriptiveDeclKind, DeclName))
 ERROR(actor_isolated_call,none,
       "call to %0 function in a synchronous %1 context",
       (ActorIsolation, ActorIsolation))

include/swift/AST/Import.h

@@ -82,7 +82,7 @@ enum class ImportFlags {
 
   /// The module is imported assuming that the module itself predates
   /// concurrency.
-  PredatesConcurrency = 0x20,
+  Preconcurrency = 0x20,
 
   /// Used for DenseMap.
   Reserved = 0x80
@@ -550,17 +550,17 @@ struct AttributedImport {
   /// Names of explicitly imported SPI groups.
   ArrayRef<Identifier> spiGroups;
 
-  /// When the import declaration has a `@_predatesConcurrency` annotation, this
+  /// When the import declaration has a `@preconcurrency` annotation, this
   /// is the source range covering the annotation.
-  SourceRange predatesConcurrencyRange;
+  SourceRange preconcurrencyRange;
 
   AttributedImport(ModuleInfo module, SourceLoc importLoc = SourceLoc(),
                    ImportOptions options = ImportOptions(),
                    StringRef filename = {}, ArrayRef<Identifier> spiGroups = {},
-                   SourceRange predatesConcurrencyRange = {})
+                   SourceRange preconcurrencyRange = {})
       : module(module), importLoc(importLoc), options(options),
         sourceFileArg(filename), spiGroups(spiGroups),
-        predatesConcurrencyRange(predatesConcurrencyRange) {
+        preconcurrencyRange(preconcurrencyRange) {
     assert(!(options.contains(ImportFlags::Exported) &&
              options.contains(ImportFlags::ImplementationOnly)) ||
            options.contains(ImportFlags::Reserved));
@@ -570,7 +570,7 @@ struct AttributedImport {
   AttributedImport(ModuleInfo module, AttributedImport<OtherModuleInfo> other)
     : AttributedImport(module, other.importLoc, other.options,
                        other.sourceFileArg, other.spiGroups,
-                       other.predatesConcurrencyRange) { }
+                       other.preconcurrencyRange) { }
 
   friend bool operator==(const AttributedImport<ModuleInfo> &lhs,
                          const AttributedImport<ModuleInfo> &rhs) {

include/swift/AST/SourceFile.h

@@ -84,9 +84,9 @@ class SourceFile final : public FileUnit {
   /// This is \c None until it is filled in by the import resolution phase.
   Optional<ArrayRef<AttributedImport<ImportedModule>>> Imports;
 
-  /// Which imports have made use of @_predatesConcurrency.
+  /// Which imports have made use of @preconcurrency.
   llvm::SmallDenseSet<AttributedImport<ImportedModule>>
-      PredatesConcurrencyImportsUsed;
+      PreconcurrencyImportsUsed;
 
   /// A unique identifier representing this file; used to mark private decls
   /// within the file to keep them from conflicting with other files in the
@@ -301,12 +301,12 @@ class SourceFile final : public FileUnit {
   /// resolution.
   void setImports(ArrayRef<AttributedImport<ImportedModule>> imports);
 
-  /// Whether the given import has used @_predatesConcurrency.
-  bool hasImportUsedPredatesConcurrency(
+  /// Whether the given import has used @preconcurrency.
+  bool hasImportUsedPreconcurrency(
       AttributedImport<ImportedModule> import) const;
 
-  /// Note that the given import has used @_predatesConcurrency/
-  void setImportUsedPredatesConcurrency(
+  /// Note that the given import has used @preconcurrency/
+  void setImportUsedPreconcurrency(
       AttributedImport<ImportedModule> import);
 
   enum ImportQueryKind {

include/swift/AST/Types.h

@@ -5666,14 +5666,14 @@ class OpenedArchetypeType final : public ArchetypeType,
   /// \param knownID When non-empty, the known ID of the archetype. When empty,
   /// a fresh archetype with a unique ID will be opened.
   static CanTypeWrapper<OpenedArchetypeType>
-                        get(Type existential,
+                        get(CanType existential,
                             Optional<UUID> knownID = None);
 
   /// Create a new archetype that represents the opened type
   /// of an existential value.
   ///
   /// \param existential The existential type or existential metatype to open.
-  static CanType getAny(Type existential);
+  static CanType getAny(CanType existential);
 
   /// Retrieve the ID number of this opened existential.
   UUID getOpenedExistentialID() const { return ID; }

include/swift/Demangling/DemangleNodes.def

@@ -325,5 +325,8 @@ NODE(IndexSubset)
 NODE(AsyncAwaitResumePartialFunction)
 NODE(AsyncSuspendResumePartialFunction)
 
+// Added in Swift 5.6
+NODE(CompileTimeConst)
+
 #undef CONTEXT_NODE
 #undef NODE

include/swift/SIL/OwnershipUtils.h

@@ -1203,7 +1203,7 @@ void findTransitiveReborrowBaseValuePairs(
 /// Given a begin of a borrow scope, visit all end_borrow users of the borrow or
 /// its reborrows.
 void visitTransitiveEndBorrows(
-    BorrowedValue beginBorrow,
+    SILValue value,
     function_ref<void(EndBorrowInst *)> visitEndBorrow);
 
 /// Whether the specified lexical begin_borrow instruction is nested.