[ASTGen] ParamDecl generation improvements

include/swift/AST/ASTBridging.h

@@ -631,6 +631,15 @@ SWIFT_NAME("getter:BridgedPatternBindingInitializer.asDeclContext(self:)")
 BridgedDeclContext BridgedPatternBindingInitializer_asDeclContext(
     BridgedPatternBindingInitializer cInit);
 
+SWIFT_NAME("BridgedDefaultArgumentInitializer.create(declContext:index:)")
+BridgedDefaultArgumentInitializer
+BridgedDefaultArgumentInitializer_create(BridgedDeclContext cDeclContext,
+                                         size_t index);
+
+SWIFT_NAME("getter:BridgedDefaultArgumentInitializer.asDeclContext(self:)")
+BridgedDeclContext DefaultArgumentInitializer_asDeclContext(
+    BridgedDefaultArgumentInitializer cInit);
+
 SWIFT_NAME("BridgedCustomAttributeInitializer.create(declContext:)")
 BridgedCustomAttributeInitializer
 BridgedCustomAttributeInitializer_create(BridgedDeclContext cDeclContext);
@@ -1302,13 +1311,15 @@ BridgedPatternBindingDecl BridgedPatternBindingDecl_createParsed(
     BridgedVarDeclIntroducer cIntorducer, BridgedArrayRef cBindingEntries);
 
 SWIFT_NAME("BridgedParamDecl.createParsed(_:declContext:specifierLoc:argName:"
-           "argNameLoc:paramName:paramNameLoc:type:defaultValue:)")
+           "argNameLoc:paramName:paramNameLoc:type:defaultValue:"
+           "defaultValueInitContext:)")
 BridgedParamDecl BridgedParamDecl_createParsed(
     BridgedASTContext cContext, BridgedDeclContext cDeclContext,
     BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cArgName,
     BridgedSourceLoc cArgNameLoc, BridgedIdentifier cParamName,
     BridgedSourceLoc cParamNameLoc, BridgedNullableTypeRepr type,
-    BridgedNullableExpr defaultValue);
+    BridgedNullableExpr defaultValue,
+    BridgedNullableDefaultArgumentInitializer cDefaultArgumentInitContext);
 
 /// The various spellings of ownership modifier that can be used in source.
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedParamSpecifier {

include/swift/AST/ASTBridgingWrappers.def

@@ -108,6 +108,7 @@ AST_BRIDGING_WRAPPER_NULLABLE(GenericParamList)
 AST_BRIDGING_WRAPPER_NULLABLE(TrailingWhereClause)
 AST_BRIDGING_WRAPPER_NULLABLE(ParameterList)
 AST_BRIDGING_WRAPPER_NULLABLE(PatternBindingInitializer)
+AST_BRIDGING_WRAPPER_NULLABLE(DefaultArgumentInitializer)
 AST_BRIDGING_WRAPPER_NULLABLE(CustomAttributeInitializer)
 AST_BRIDGING_WRAPPER_NONNULL(TypeAttributes)
 AST_BRIDGING_WRAPPER_NONNULL(CustomAttribute)

include/swift/AST/Decl.h

@@ -6859,6 +6859,7 @@ class VarDecl : public AbstractStorageDecl {
 
 /// A function parameter declaration.
 class ParamDecl : public VarDecl {
+  friend class ParameterList;
   friend class DefaultArgumentInitContextRequest;
   friend class DefaultArgumentExprRequest;
   friend class DefaultArgumentTypeRequest;
@@ -6885,15 +6886,17 @@ class ParamDecl : public VarDecl {
 
     /// Stores the context for the default argument as well as a bit to
     /// indicate whether the default expression has been type-checked.
-    llvm::PointerIntPair<Initializer *, 1, bool> InitContextAndIsTypeChecked;
+    llvm::PointerIntPair<DefaultArgumentInitializer *, 1, bool>
+        InitContextAndIsTypeChecked;
 
     StringRef StringRepresentation;
     CaptureInfo Captures;
   };
 
   /// Retrieve the cached initializer context for the parameter's default
   /// argument without triggering a request.
-  std::optional<Initializer *> getCachedDefaultArgumentInitContext() const;
+  std::optional<DefaultArgumentInitializer *>
+  getCachedDefaultArgumentInitContext() const;
 
   /// NOTE: This is stored using bits from TyReprAndFlags and
   /// DefaultValueAndFlags.
@@ -7002,12 +7005,11 @@ class ParamDecl : public VarDecl {
                  DeclContext *Parent,
                  ParamSpecifier specifier = ParamSpecifier::Default);
 
-  static ParamDecl *createParsed(ASTContext &Context, SourceLoc specifierLoc,
-                                 SourceLoc argumentNameLoc,
-                                 Identifier argumentName,
-                                 SourceLoc parameterNameLoc,
-                                 Identifier parameterName, Expr *defaultValue,
-                                 DeclContext *dc);
+  static ParamDecl *createParsed(
+      ASTContext &Context, SourceLoc specifierLoc, SourceLoc argumentNameLoc,
+      Identifier argumentName, SourceLoc parameterNameLoc,
+      Identifier parameterName, Expr *defaultValue,
+      DefaultArgumentInitializer *defaultValueInitContext, DeclContext *dc);
 
   /// Retrieve the argument (API) name for this function parameter.
   Identifier getArgumentName() const {
@@ -7118,7 +7120,7 @@ class ParamDecl : public VarDecl {
   /// Retrieve the initializer context for the parameter's default argument.
   Initializer *getDefaultArgumentInitContext() const;
 
-  void setDefaultArgumentInitContext(Initializer *initContext);
+  void setDefaultArgumentInitContext(DefaultArgumentInitializer *initContext);
 
   CaptureInfo getDefaultArgumentCaptureInfo() const;
 

include/swift/AST/Initializer.h

@@ -126,18 +126,24 @@ class PatternBindingInitializer : public Initializer {
 /// A default argument expression.  The parent context is the function
 /// (possibly a closure) for which this is a default argument.
 class DefaultArgumentInitializer : public Initializer {
-public:
   explicit DefaultArgumentInitializer(DeclContext *parent, unsigned index)
       : Initializer(InitializerKind::DefaultArgument, parent) {
     SpareBits = index;
   }
 
+public:
+  static DefaultArgumentInitializer *create(DeclContext *parent,
+                                            unsigned index) {
+    return new (parent->getASTContext())
+        DefaultArgumentInitializer(parent, index);
+  }
+
   unsigned getIndex() const { return SpareBits; }
 
   /// Change the parent of this context.  This is necessary because
   /// the function signature is parsed before the function
   /// declaration/expression itself is built.
-  void changeFunction(DeclContext *parent, ParameterList *paramLists);
+  void changeFunction(DeclContext *parent);
 
   static bool classof(const DeclContext *DC) {
     if (auto init = dyn_cast<Initializer>(DC))

include/swift/AST/TypeCheckRequests.h

@@ -3136,7 +3136,7 @@ class DistributedModuleIsAvailableRequest
 /// Computes an initializer context for a parameter with a default argument.
 class DefaultArgumentInitContextRequest
     : public SimpleRequest<DefaultArgumentInitContextRequest,
-                           Initializer *(ParamDecl *),
+                           DefaultArgumentInitializer *(ParamDecl *),
                            RequestFlags::SeparatelyCached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -3145,14 +3145,14 @@ class DefaultArgumentInitContextRequest
   friend SimpleRequest;
 
   // Evaluation.
-  Initializer * evaluate(Evaluator &evaluator,
-                                         ParamDecl *param) const;
+  DefaultArgumentInitializer *evaluate(Evaluator &evaluator,
+                                       ParamDecl *param) const;
 
 public:
   // Separate caching.
   bool isCached() const { return true; }
-  std::optional<Initializer *> getCachedResult() const;
-  void cacheResult(Initializer *init) const;
+  std::optional<DefaultArgumentInitializer *> getCachedResult() const;
+  void cacheResult(DefaultArgumentInitializer *init) const;
 };
 
 /// Computes the fully type-checked default argument expression for a given

include/swift/Parse/Parser.h

@@ -1504,7 +1504,6 @@ class Parser {
   /// A structure for collecting information about the default
   /// arguments of a context.
   struct DefaultArgumentInfo {
-    llvm::SmallVector<DefaultArgumentInitializer *, 4> ParsedContexts;
     unsigned NextIndex : 31;
 
     /// Track whether or not one of the parameters in a signature's argument
@@ -1515,10 +1514,6 @@ class Parser {
     /// all the arguments, not just those that have default arguments.
     unsigned claimNextIndex() { return NextIndex++; }
 
-    /// Set the parsed context of all default argument initializers to
-    /// the given function, enum case or subscript.
-    void setFunctionContext(DeclContext *DC, ParameterList *paramList);
-
     DefaultArgumentInfo() {
       NextIndex = 0;
       HasDefaultArgument = false;
@@ -1567,6 +1562,9 @@ class Parser {
     /// The default argument for this parameter.
     Expr *DefaultArg = nullptr;
 
+    /// The default argument for this parameter.
+    DefaultArgumentInitializer *DefaultArgInitContext = nullptr;
+
     /// True if we emitted a parse error about this parameter.
     bool isInvalid = false;
 

lib/AST/Bridging/DeclBridging.cpp

@@ -194,11 +194,13 @@ BridgedParamDecl BridgedParamDecl_createParsed(
     BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cArgName,
     BridgedSourceLoc cArgNameLoc, BridgedIdentifier cParamName,
     BridgedSourceLoc cParamNameLoc, BridgedNullableTypeRepr opaqueType,
-    BridgedNullableExpr opaqueDefaultValue) {
+    BridgedNullableExpr cDefaultArgument,
+    BridgedNullableDefaultArgumentInitializer cDefaultArgumentInitContext) {
   auto *paramDecl = ParamDecl::createParsed(
       cContext.unbridged(), cSpecifierLoc.unbridged(), cArgNameLoc.unbridged(),
       cArgName.unbridged(), cParamNameLoc.unbridged(), cParamName.unbridged(),
-      opaqueDefaultValue.unbridged(), cDeclContext.unbridged());
+      cDefaultArgument.unbridged(), cDefaultArgumentInitContext.unbridged(),
+      cDeclContext.unbridged());
 
   if (auto type = opaqueType.unbridged()) {
     paramDecl->setTypeRepr(type);

lib/AST/Bridging/DeclContextBridging.cpp

@@ -31,6 +31,17 @@ BridgedDeclContext BridgedPatternBindingInitializer_asDeclContext(
   return cInit.unbridged();
 }
 
+BridgedDefaultArgumentInitializer
+BridgedDefaultArgumentInitializer_create(BridgedDeclContext cDeclContext,
+                                         size_t index) {
+  return DefaultArgumentInitializer::create(cDeclContext.unbridged(), index);
+}
+
+BridgedDeclContext DefaultArgumentInitializer_asDeclContext(
+    BridgedDefaultArgumentInitializer cInit) {
+  return cInit.unbridged();
+}
+
 BridgedCustomAttributeInitializer
 BridgedCustomAttributeInitializer_create(BridgedDeclContext cDeclContext) {
   return CustomAttributeInitializer::create(cDeclContext.unbridged());

lib/AST/Decl.cpp

@@ -8686,27 +8686,30 @@ static DefaultArgumentKind computeDefaultArgumentKind(DeclContext *dc,
   llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
 }
 
-ParamDecl *ParamDecl::createParsed(ASTContext &Context, SourceLoc specifierLoc,
-                                   SourceLoc argumentNameLoc,
-                                   Identifier argumentName,
-                                   SourceLoc parameterNameLoc,
-                                   Identifier parameterName, Expr *defaultValue,
-                                   DeclContext *dc) {
+ParamDecl *ParamDecl::createParsed(
+    ASTContext &Context, SourceLoc specifierLoc, SourceLoc argumentNameLoc,
+    Identifier argumentName, SourceLoc parameterNameLoc,
+    Identifier parameterName, Expr *defaultValue,
+    DefaultArgumentInitializer *defaultValueInitContext, DeclContext *dc) {
   auto *decl =
       new (Context) ParamDecl(specifierLoc, argumentNameLoc, argumentName,
                               parameterNameLoc, parameterName, dc);
 
-  const auto kind = computeDefaultArgumentKind(dc, defaultValue);
-  if (kind == DefaultArgumentKind::Inherited) {
-    // The 'super' in inherited default arguments is a specifier rather than an
-    // expression.
-    // TODO: However, we may want to retain its location for diagnostics.
-    defaultValue = nullptr;
+  if (defaultValue) {
+    const auto kind = computeDefaultArgumentKind(dc, defaultValue);
+    if (kind == DefaultArgumentKind::Inherited) {
+      // The 'super' in inherited default arguments is a specifier rather than
+      // an expression.
+      // TODO: However, we may want to retain its location for diagnostics.
+      defaultValue = nullptr;
+    }
+    ASSERT(defaultValueInitContext);
+    decl->setDefaultExpr(defaultValue);
+    decl->setDefaultArgumentKind(kind);
+    if (defaultValue)
+      decl->setDefaultArgumentInitContext(defaultValueInitContext);
   }
 
-  decl->setDefaultExpr(defaultValue);
-  decl->setDefaultArgumentKind(kind);
-
   return decl;
 }
 
@@ -8870,7 +8873,7 @@ AnyFunctionType::Param ParamDecl::toFunctionParam(Type type) const {
   return AnyFunctionType::Param(type, label, flags, internalLabel);
 }
 
-std::optional<Initializer *>
+std::optional<DefaultArgumentInitializer *>
 ParamDecl::getCachedDefaultArgumentInitContext() const {
   if (auto *defaultInfo = DefaultValueAndFlags.getPointer())
     if (auto *init = defaultInfo->InitContextAndIsTypeChecked.getPointer())
@@ -9043,7 +9046,8 @@ CustomAttr *ValueDecl::getAttachedResultBuilder() const {
                            nullptr);
 }
 
-void ParamDecl::setDefaultArgumentInitContext(Initializer *initContext) {
+void ParamDecl::setDefaultArgumentInitContext(
+    DefaultArgumentInitializer *initContext) {
   auto oldContext = getCachedDefaultArgumentInitContext();
   assert((!oldContext || oldContext == initContext) &&
          "Cannot change init context after setting");
@@ -9246,15 +9250,9 @@ ParamDecl::setDefaultValueStringRepresentation(StringRef stringRepresentation) {
       stringRepresentation;
 }
 
-void DefaultArgumentInitializer::changeFunction(
-    DeclContext *parent, ParameterList *paramList) {
-  if (parent->isLocalContext()) {
-    setParent(parent);
-  }
-
-  auto param = paramList->get(getIndex());
-  if (param->hasDefaultExpr() || param->getStoredProperty())
-    param->setDefaultArgumentInitContext(this);
+void DefaultArgumentInitializer::changeFunction(DeclContext *parent) {
+  ASSERT(parent->isLocalContext());
+  setParent(parent);
 }
 
 /// Determine whether the given Swift type is an integral type, i.e.,

lib/AST/Parameter.cpp

@@ -45,8 +45,11 @@ ParameterList::create(const ASTContext &C, SourceLoc LParenLoc,
 /// Change the DeclContext of any contained parameters to the specified
 /// DeclContext.
 void ParameterList::setDeclContextOfParamDecls(DeclContext *DC) {
-  for (auto P : *this)
+  for (ParamDecl *P : *this) {
     P->setDeclContext(DC);
+    if (auto initContext = P->getCachedDefaultArgumentInitContext())
+      (*initContext)->changeFunction(DC);
+  }
 }
 
 /// Make a duplicate copy of this parameter list.  This allocates copies of

lib/AST/TypeCheckRequests.cpp

@@ -1404,13 +1404,14 @@ void HasCircularRawValueRequest::noteCycleStep(DiagnosticEngine &diags) const {
 // DefaultArgumentInitContextRequest computation.
 //----------------------------------------------------------------------------//
 
-std::optional<Initializer *>
+std::optional<DefaultArgumentInitializer *>
 DefaultArgumentInitContextRequest::getCachedResult() const {
   auto *param = std::get<0>(getStorage());
   return param->getCachedDefaultArgumentInitContext();
 }
 
-void DefaultArgumentInitContextRequest::cacheResult(Initializer *init) const {
+void DefaultArgumentInitContextRequest::cacheResult(
+    DefaultArgumentInitializer *init) const {
   auto *param = std::get<0>(getStorage());
   param->setDefaultArgumentInitContext(init);
 }

lib/ASTGen/Sources/ASTGen/Bridge.swift

@@ -36,6 +36,7 @@ extension BridgedNullableGenericParamList: /*@retroactive*/ swiftASTGen.BridgedN
 extension BridgedNullableTrailingWhereClause: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableParameterList: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullablePatternBindingInitializer: /*@retroactive*/ swiftASTGen.BridgedNullable {}
+extension BridgedNullableDefaultArgumentInitializer: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableCustomAttributeInitializer: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableArgumentList: /*@retroactive*/ swiftASTGen.BridgedNullable {}
 extension BridgedNullableVarDecl: /*@retroactive*/ swiftASTGen.BridgedNullable {}
@@ -87,6 +88,9 @@ extension BridgedParameterList: BridgedHasNullable {
 extension BridgedPatternBindingInitializer: BridgedHasNullable {
   typealias Nullable = BridgedNullablePatternBindingInitializer
 }
+extension BridgedDefaultArgumentInitializer: BridgedHasNullable {
+  typealias Nullable = BridgedNullableDefaultArgumentInitializer
+}
 extension BridgedCustomAttributeInitializer: BridgedHasNullable {
   typealias Nullable = BridgedNullableCustomAttributeInitializer
 }

lib/ASTGen/Sources/ASTGen/Exprs.swift

@@ -366,7 +366,8 @@ extension ASTGenVisitor {
             paramName: ctx.getDollarIdentifier(idx),
             paramNameLoc: loc,
             type: nil,
-            defaultValue: nil
+            defaultValue: nil,
+            defaultValueInitContext: nil
           )
           param.setSpecifier(.default)
           param.setImplicit()