[ASTGen] Transform @_inheritActorContext into a custom attribute with an optional modifier

include/swift/AST/ASTBridging.h

@@ -1254,6 +1254,18 @@ BridgedNonisolatedAttr_createParsed(BridgedASTContext cContext,
                                     BridgedSourceRange cRange,
                                     BridgedNonIsolatedModifier modifier);
 
+enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedInheritActorContextModifier {
+  BridgedInheritActorContextModifierNone,
+  BridgedInheritActorContextModifierAlways,
+};
+
+SWIFT_NAME("BridgedInheritActorContextAttr.createParsed(_:atLoc:range:modifier:)")
+BridgedInheritActorContextAttr
+BridgedInheritActorContextAttr_createParsed(BridgedASTContext cContext,
+                                            BridgedSourceLoc cAtLoc,
+                                            BridgedSourceRange cRange,
+                                            BridgedInheritActorContextModifier modifier);
+
 SWIFT_NAME("BridgedObjCAttr.createParsedUnnamed(_:atLoc:attrNameLoc:)")
 BridgedObjCAttr
 BridgedObjCAttr_createParsedUnnamed(BridgedASTContext cContext,

lib/AST/Bridging/DeclAttributeBridging.cpp

@@ -649,6 +649,25 @@ BridgedNonisolatedAttr_createParsed(BridgedASTContext cContext,
       /*implicit=*/false);
 }
 
+static InheritActorContextModifier
+unbridged(BridgedInheritActorContextModifier modifier) {
+  switch (modifier) {
+  case BridgedInheritActorContextModifierNone:
+    return InheritActorContextModifier::None;
+  case BridgedInheritActorContextModifierAlways:
+    return InheritActorContextModifier::Always;
+  }
+  llvm_unreachable("unhandled enum value");
+}
+
+BridgedInheritActorContextAttr BridgedInheritActorContextAttr_createParsed(
+    BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
+    BridgedSourceRange cRange, BridgedInheritActorContextModifier modifier) {
+  return new (cContext.unbridged()) InheritActorContextAttr(
+      cAtLoc.unbridged(), cRange.unbridged(), unbridged(modifier),
+      /*implicit=*/false);
+}
+
 BridgedObjCAttr
 BridgedObjCAttr_createParsedUnnamed(BridgedASTContext cContext,
                                     BridgedSourceLoc cAtLoc,

lib/ASTGen/Sources/ASTGen/DeclAttrs.swift

@@ -249,7 +249,6 @@ extension ASTGenVisitor {
         .ibSegueAction,
         .implementationOnly,
         .implicitSelfCapture,
-        .inheritActorContext,
         .inheritsConvenienceInitializers,
         .inlinable,
         .isolated,
@@ -312,6 +311,9 @@ extension ASTGenVisitor {
       case .referenceOwnership:
         // TODO: Diagnose.
         return handle(self.generateReferenceOwnershipAttr(attribute: node, attrName: attrName)?.asDeclAttribute)
+      case .inheritActorContext:
+        return handle(self.generateInheritActorContextAttr(attribute: node)?.asDeclAttribute)
+
       case .async,
         .consuming,
         .borrowing,
@@ -1411,6 +1413,28 @@ extension ASTGenVisitor {
     )
   }
 
+  func generateInheritActorContextAttr(attribute node: AttributeSyntax) -> BridgedInheritActorContextAttr? {
+    let modifier: BridgedInheritActorContextModifier? = self.generateSingleAttrOption(
+      attribute: node,
+      {
+        switch $0.rawText {
+        case "always": return .always
+        default: return nil
+        }
+      },
+      valueIfOmitted: BridgedInheritActorContextModifier.none
+    )
+    guard let modifier else {
+      return nil
+    }
+    return .createParsed(
+      self.ctx,
+      atLoc: self.generateSourceLoc(node.atSign),
+      range: self.generateAttrSourceRange(node),
+      modifier: modifier
+    )
+  }
+
   /// E.g.:
   ///   ```
   ///   @objc

test/ASTGen/attrs.swift

@@ -256,3 +256,6 @@ struct LayoutOuter {
 struct AnyEraser: EraserProto {
   init<T: EraserProto>(erasing: T) {}
 }
+
+func takeNone(@_inheritActorContext param: () async -> ()) { }
+func takeAlways(@_inheritActorContext(always) param: () async -> ()) { }