Merge pull request #42412 from plotfi/c-enums-withOptions-omit

[C++-Interop] Teach omitNeedlessWords to handle raw integer C-enums in C++

Author: zoecarver

lib/ClangImporter/ImportType.cpp

@@ -2465,6 +2465,19 @@ DefaultArgumentKind ClangImporter::Implementation::inferDefaultArgument(
           return DefaultArgumentKind::EmptyArray;
       }
     }
+  } else if (const clang::TypedefType *typedefType =
+                 type->getAs<clang::TypedefType>()) {
+    // Get the AvailabilityAttr that would be set from CF/NS_OPTIONS
+    if (importer::isUnavailableInSwift(typedefType->getDecl(), nullptr, true)) {
+      // If we've taken this branch it means we have an enum type, and it is
+      // likely an integer or NSInteger that is being used by NS/CF_OPTIONS to
+      // behave like a C enum in the presence of C++.
+      auto enumName = typedefType->getDecl()->getDeclName().getAsString();
+      for (auto word : llvm::reverse(camel_case::getWords(enumName))) {
+        if (camel_case::sameWordIgnoreFirstCase(word, "options"))
+          return DefaultArgumentKind::EmptyArray;
+      }
+    }
   }
 
   // NSDictionary arguments default to [:] (or nil, if nullable) if "options",

test/Interop/Cxx/enum/Inputs/c-enums-withOptions-omit.h

@@ -0,0 +1,8 @@
+// Enum usage that is bitwise-able and assignable in C++, aka how CF_OPTIONS
+// does things.
+typedef int __attribute__((availability(swift, unavailable))) NSEnumerationOptions;
+enum : NSEnumerationOptions { NSEnumerationConcurrent, NSEnumerationReverse };
+
+@interface NSSet
+- (void)enumerateObjectsWithOptions:(NSEnumerationOptions)opts ;
+@end

test/Interop/Cxx/enum/Inputs/module.modulemap

@@ -12,3 +12,8 @@ module AnonymousWithSwiftName {
   header "anonymous-with-swift-name.h"
   requires cplusplus
 }
+
+module CenumsWithOptionsOmit {
+  header "c-enums-withOptions-omit.h"
+  requires cplusplus
+}

test/Interop/Cxx/enum/c-enums-withOptions-omit.swift

@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=CenumsWithOptionsOmit -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
+// REQUIRES: objc_interop
+
+import CenumsWithOptionsOmit
+
+// CHECK: class NSSet {
+// CHECK-NEXT: class func enumerateObjects(options
+// CHECK-NEXT: func enumerateObjects(options
+// CHECK-NEXT: @available(swift, obsoleted: 3, renamed: "enumerateObjects(options:)")