Revert "AsyncSequence and protocol conformance rethrows"

include/swift/AST/ASTContext.h

@@ -522,9 +522,6 @@ class ASTContext final {
   /// Get Sequence.makeIterator().
   FuncDecl *getSequenceMakeIterator() const;
 
-  /// Get AsyncSequence.makeAsyncIterator().
-  FuncDecl *getAsyncSequenceMakeAsyncIterator() const;
-
   /// Check whether the standard library provides all the correct
   /// intrinsic support for Optional<T>.
   ///

include/swift/AST/ASTTypeIDZone.def

@@ -31,8 +31,6 @@ SWIFT_TYPEID(PropertyWrapperTypeInfo)
 SWIFT_TYPEID(Requirement)
 SWIFT_TYPEID(ResilienceExpansion)
 SWIFT_TYPEID(FragileFunctionKind)
-SWIFT_TYPEID(FunctionRethrowingKind)
-SWIFT_TYPEID(ProtocolRethrowsRequirementList)
 SWIFT_TYPEID(TangentPropertyInfo)
 SWIFT_TYPEID(SymbolSourceMap)
 SWIFT_TYPEID(Type)

include/swift/AST/ASTTypeIDs.h

@@ -64,8 +64,6 @@ class ProtocolDecl;
 class Requirement;
 enum class ResilienceExpansion : unsigned;
 struct FragileFunctionKind;
-enum class FunctionRethrowingKind : uint8_t;
-class ProtocolRethrowsRequirementList;
 class SourceFile;
 class SymbolSourceMap;
 struct TangentPropertyInfo;

include/swift/AST/Attr.def

@@ -359,10 +359,6 @@ SIMPLE_DECL_ATTR(rethrows, Rethrows,
   RejectByParser |
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   57)
-SIMPLE_DECL_ATTR(rethrows, AtRethrows,
-  OnProtocol |
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
-  58)
 DECL_ATTR(_swift_native_objc_runtime_base, SwiftNativeObjCRuntimeBase,
   OnClass |
   UserInaccessible |

include/swift/AST/Decl.h

@@ -3879,66 +3879,6 @@ enum class KnownDerivableProtocolKind : uint8_t {
   Actor,
 };
 
-class ProtocolRethrowsRequirementList {
-public:
-  typedef std::pair<Type, ValueDecl *> Entry;
-
-private:
-  ArrayRef<Entry> entries;
-
-public:
-  ProtocolRethrowsRequirementList(ArrayRef<Entry> entries) : entries(entries) {}
-  ProtocolRethrowsRequirementList() : entries() {}
-
-  typedef const Entry *const_iterator;
-  typedef const_iterator iterator;
-
-  const_iterator begin() const { return entries.begin(); }
-  const_iterator end() const { return entries.end(); }
-
-  size_t size() const { return entries.size(); }
-
-  void print(raw_ostream &OS) const;
-
-  SWIFT_DEBUG_DUMP;
-
-  friend bool operator==(const ProtocolRethrowsRequirementList &lhs,
-                         const ProtocolRethrowsRequirementList &rhs) {
-    if (lhs.size() != rhs.size()) {
-      return false;
-    }
-    auto lhsIter = lhs.begin();
-    auto rhsIter = rhs.begin();
-    while (lhsIter != lhs.end() && rhsIter != rhs.end()) {
-      if (lhsIter->first->isEqual(rhsIter->first)) {
-        return false;
-      }
-      if (lhsIter->second != rhsIter->second) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  friend bool operator!=(const ProtocolRethrowsRequirementList &lhs,
-                         const ProtocolRethrowsRequirementList &rhs) {
-    return !(lhs == rhs);
-  }
-
-  friend llvm::hash_code hash_value(
-    const ProtocolRethrowsRequirementList &list) {
-    return llvm::hash_combine(list.size()); // it is good enought for
-    // llvm::hash_code hash;
-    // for (auto entry : list) {
-    //   hash = llvm::hash_combine(hash, entry.first->getCanonicalType());
-    //   hash = llvm::hash_combine(hash, entry.second);
-    // }
-    // return hash;
-  }
-};
-
-void simple_display(raw_ostream &out, const ProtocolRethrowsRequirementList reqs);
-
 /// ProtocolDecl - A declaration of a protocol, for example:
 ///
 ///   protocol Drawable {
@@ -4120,9 +4060,6 @@ class ProtocolDecl final : public NominalTypeDecl {
   /// contain 'Self' in 'parameter' or 'other' position.
   bool existentialTypeSupported() const;
 
-  ProtocolRethrowsRequirementList getRethrowingRequirements() const;
-  bool isRethrowingProtocol() const;
-
 private:
   void computeKnownProtocolKind() const;
 
@@ -5532,23 +5469,6 @@ class ImportAsMemberStatus {
   }
 };
 
-enum class FunctionRethrowingKind : uint8_t {
-  /// The function is not throwing
-  None,
-
-  /// The function rethrows by closure
-  ByClosure, 
-
-  /// The function rethrows by conformance
-  ByConformance, 
-
-  /// The function throws
-  Throws, 
-
-  /// The function throwing determinate is invalid
-  Invalid
-};
-
 /// Base class for function-like declarations.
 class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   friend class NeedsNewVTableEntryRequest;
@@ -5751,8 +5671,6 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// Returns true if the function body throws.
   bool hasThrows() const { return Bits.AbstractFunctionDecl.Throws; }
 
-  FunctionRethrowingKind getRethrowingKind() const;
-
   // FIXME: Hack that provides names with keyword arguments for accessors.
   DeclName getEffectiveFullName() const;
 

include/swift/AST/DiagnosticsSema.def

@@ -2983,8 +2983,6 @@ ERROR(override_rethrows_with_non_rethrows,none,
       "be 'rethrows'", (bool))
 ERROR(rethrows_without_throwing_parameter,none,
       "'rethrows' function must take a throwing function argument", ())
-ERROR(rethrows_attr_on_non_protocol,none,
-      "@rethrows may only be used on 'protocol' declarations", ())
 
 ERROR(autoclosure_function_type,none,
       "@autoclosure attribute only applies to function types",
@@ -4061,8 +4059,6 @@ NOTE(because_rethrows_argument_throws,none,
 NOTE(because_rethrows_default_argument_throws,none,
      "call is to 'rethrows' function, but a defaulted argument function"
      " can throw", ())
-NOTE(because_rethrows_default_conformance_throws,none,
-     "call is to 'rethrows' function, but a conformance has a throwing witness", ())
 
 ERROR(throwing_call_in_nonthrowing_autoclosure,none,
       "call can throw, but it is executed in a non-throwing "

include/swift/AST/KnownIdentifiers.def

@@ -93,9 +93,7 @@ IDENTIFIER(KeyedEncodingContainer)
 IDENTIFIER(keyedBy)
 IDENTIFIER(keyPath)
 IDENTIFIER(makeIterator)
-IDENTIFIER(makeAsyncIterator)
 IDENTIFIER(Iterator)
-IDENTIFIER(AsyncIterator)
 IDENTIFIER(load)
 IDENTIFIER(main)
 IDENTIFIER_WITH_NAME(MainEntryPoint, "$main")

include/swift/AST/KnownProtocols.def

@@ -88,9 +88,6 @@ PROTOCOL(StringInterpolationProtocol)
 PROTOCOL(AdditiveArithmetic)
 PROTOCOL(Differentiable)
 
-PROTOCOL(AsyncSequence)
-PROTOCOL(AsyncIteratorProtocol)
-
 PROTOCOL(FloatingPoint)
 
 EXPRESSIBLE_BY_LITERAL_PROTOCOL(ExpressibleByArrayLiteral, "Array", false)

include/swift/AST/ProtocolConformanceRef.h

@@ -170,13 +170,8 @@ class ProtocolConformanceRef {
   /// Get any additional requirements that are required for this conformance to
   /// be satisfied.
   ArrayRef<Requirement> getConditionalRequirements() const;
-
-  bool classifyAsThrows() const;
 };
 
-void simple_display(llvm::raw_ostream &out, ProtocolConformanceRef conformanceRef);
-SourceLoc extractNearestSourceLoc(const ProtocolConformanceRef conformanceRef);
-
 } // end namespace swift
 
 #endif // LLVM_SWIFT_AST_PROTOCOLCONFORMANCEREF_H

include/swift/AST/Stmt.h

@@ -726,8 +726,6 @@ class RepeatWhileStmt : public LabeledStmt {
 /// \endcode
 class ForEachStmt : public LabeledStmt {
   SourceLoc ForLoc;
-  SourceLoc TryLoc;
-  SourceLoc AwaitLoc;
   Pattern *Pat;
   SourceLoc InLoc;
   Expr *Sequence;
@@ -743,12 +741,12 @@ class ForEachStmt : public LabeledStmt {
   Expr *convertElementExpr = nullptr;
 
 public:
-  ForEachStmt(LabeledStmtInfo LabelInfo, SourceLoc ForLoc, SourceLoc TryLoc, SourceLoc AwaitLoc, 
-              Pattern *Pat, SourceLoc InLoc, Expr *Sequence, SourceLoc WhereLoc,
+  ForEachStmt(LabeledStmtInfo LabelInfo, SourceLoc ForLoc, Pattern *Pat,
+              SourceLoc InLoc, Expr *Sequence, SourceLoc WhereLoc,
               Expr *WhereExpr, BraceStmt *Body, Optional<bool> implicit = None)
     : LabeledStmt(StmtKind::ForEach, getDefaultImplicitFlag(implicit, ForLoc),
                   LabelInfo),
-      ForLoc(ForLoc), TryLoc(TryLoc), AwaitLoc(AwaitLoc), Pat(nullptr), InLoc(InLoc), Sequence(Sequence),
+      ForLoc(ForLoc), Pat(nullptr), InLoc(InLoc), Sequence(Sequence),
       WhereLoc(WhereLoc), WhereExpr(WhereExpr), Body(Body) {
     setPattern(Pat);
   }
@@ -780,9 +778,6 @@ class ForEachStmt : public LabeledStmt {
 
   /// getWhereLoc - Retrieve the location of the 'where' keyword.
   SourceLoc getWhereLoc() const { return WhereLoc; }
-
-  SourceLoc getAwaitLoc() const { return AwaitLoc; }
-  SourceLoc getTryLoc() const { return TryLoc; }
 
   /// getPattern - Retrieve the pattern describing the iteration variables.
   /// These variables will only be visible within the body of the loop.

include/swift/AST/TypeCheckRequests.h

@@ -311,44 +311,6 @@ class ExistentialTypeSupportedRequest :
   void cacheResult(bool value) const;
 };
 
-class ProtocolRethrowsRequirementsRequest :
-    public SimpleRequest<ProtocolRethrowsRequirementsRequest,
-                         ProtocolRethrowsRequirementList(ProtocolDecl *),
-                         RequestFlags::Cached> {
-public:
-  using SimpleRequest::SimpleRequest;
-
-private:
-  friend SimpleRequest;
-
-  // Evaluation.
-  ProtocolRethrowsRequirementList 
-  evaluate(Evaluator &evaluator, ProtocolDecl *decl) const;
-
-public:
-  // Caching.
-  bool isCached() const { return true; }
-};
-
-class ProtocolConformanceRefClassifyAsThrowsRequest : 
-    public SimpleRequest<ProtocolConformanceRefClassifyAsThrowsRequest,
-                         bool(ProtocolConformanceRef),
-                         RequestFlags::Cached> {
-public:
-  using SimpleRequest::SimpleRequest;
-
-private:
-  friend SimpleRequest;
-
-  // Evaluation.
-  bool 
-  evaluate(Evaluator &evaluator, ProtocolConformanceRef conformanceRef) const;
-
-public:
-  // Caching.
-  bool isCached() const { return true; }
-};
-
 /// Determine whether the given declaration is 'final'.
 class IsFinalRequest :
     public SimpleRequest<IsFinalRequest,
@@ -772,26 +734,6 @@ void simple_display(llvm::raw_ostream &out, FragileFunctionKind value);
 
 void simple_display(llvm::raw_ostream &out, ResilienceExpansion value);
 
-class FunctionRethrowingKindRequest :
-    public SimpleRequest<FunctionRethrowingKindRequest,
-                         FunctionRethrowingKind(AbstractFunctionDecl*),
-                         RequestFlags::Cached> {
-public:
-  using SimpleRequest::SimpleRequest;
-
-private:
-  friend SimpleRequest;
-
-  // Evaluation.
-  FunctionRethrowingKind evaluate(Evaluator &evaluator, AbstractFunctionDecl *decl) const;
-
-public:
-  // Caching.
-  bool isCached() const { return true; }
-};
-
-void simple_display(llvm::raw_ostream &out, FunctionRethrowingKind value);
-
 /// Request the custom attribute which attaches a result builder to the
 /// given declaration.
 class AttachedResultBuilderRequest :

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -211,8 +211,6 @@ SWIFT_REQUEST(TypeChecker, RequiresOpaqueModifyCoroutineRequest,
               bool(AbstractStorageDecl *), SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, FragileFunctionKindRequest,
               FragileFunctionKind(DeclContext *), Cached, NoLocationInfo)
-SWIFT_REQUEST(TypeChecker, FunctionRethrowingKindRequest,
-              FunctionRethrowingKind(AbstractFunctionDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, SelfAccessKindRequest, SelfAccessKind(FuncDecl *),
               SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, StorageImplInfoRequest,
@@ -267,12 +265,6 @@ SWIFT_REQUEST(TypeChecker, ResolveImplicitMemberRequest,
 SWIFT_REQUEST(TypeChecker, ResolveTypeEraserTypeRequest,
               Type(ProtocolDecl *, TypeEraserAttr *),
               SeparatelyCached, NoLocationInfo)
-SWIFT_REQUEST(TypeChecker, ProtocolRethrowsRequirementsRequest,
-              ProtocolRethrowsRequirementList(ProtocolDecl *), 
-              Cached, NoLocationInfo)
-SWIFT_REQUEST(TypeChecker, ProtocolConformanceRefClassifyAsThrowsRequest,
-              bool(ProtocolConformanceRef), 
-              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ResolveTypeRequest,
               Type (const TypeResolution *, TypeRepr *, GenericParamList *),
               Uncached, NoLocationInfo)

lib/AST/ASTContext.cpp

@@ -206,9 +206,6 @@ struct ASTContext::Implementation {
   /// The declaration of 'Sequence.makeIterator()'.
   FuncDecl *MakeIterator = nullptr;
 
-  /// The declaration of 'AsyncSequence.makeAsyncIterator()'.
-  FuncDecl *MakeAsyncIterator = nullptr;
-
   /// The declaration of Swift.Optional<T>.Some.
   EnumElementDecl *OptionalSomeDecl = nullptr;
 
@@ -775,31 +772,6 @@ FuncDecl *ASTContext::getSequenceMakeIterator() const {
   return nullptr;
 }
 
-FuncDecl *ASTContext::getAsyncSequenceMakeAsyncIterator() const {
-  if (getImpl().MakeAsyncIterator) {
-    return getImpl().MakeAsyncIterator;
-  }
-
-  auto proto = getProtocol(KnownProtocolKind::AsyncSequence);
-  if (!proto)
-    return nullptr;
-
-  for (auto result : proto->lookupDirect(Id_makeAsyncIterator)) {
-    if (result->getDeclContext() != proto)
-      continue;
-
-    if (auto func = dyn_cast<FuncDecl>(result)) {
-      if (func->getParameters()->size() != 0)
-        continue;
-
-      getImpl().MakeAsyncIterator = func;
-      return func;
-    }
-  }
-
-  return nullptr;
-}
-
 #define KNOWN_STDLIB_TYPE_DECL(NAME, DECL_CLASS, NUM_GENERIC_PARAMS) \
   DECL_CLASS *ASTContext::get##NAME##Decl() const { \
     if (getImpl().NAME##Decl) \
@@ -971,8 +943,6 @@ ProtocolDecl *ASTContext::getProtocol(KnownProtocolKind kind) const {
     M = getLoadedModule(Id_Differentiation);
     break;
   case KnownProtocolKind::Actor:
-  case KnownProtocolKind::AsyncSequence:
-  case KnownProtocolKind::AsyncIteratorProtocol:
     M = getLoadedModule(Id_Concurrency);
     break;
   default: