[cxx-interop] Fix sema lookup scope so we find NSNotification interface even in C++ mode.

Author: zoecarver

lib/ClangImporter/ClangAdapter.cpp

@@ -554,7 +554,7 @@ clang::TypedefNameDecl *importer::findSwiftNewtype(const clang::NamedDecl *decl,
     clang::LookupResult lookupResult(clangSema, notificationName,
                                      clang::SourceLocation(),
                                      clang::Sema::LookupOrdinaryName);
-    if (!clangSema.LookupName(lookupResult, nullptr))
+    if (!clangSema.LookupName(lookupResult, clangSema.TUScope))
       return nullptr;
     auto nsDecl = lookupResult.getAsSingle<clang::TypedefNameDecl>();
     if (!nsDecl)

test/Interop/Cxx/objc-correctness/Inputs/nsnotification-bridging.h

@@ -0,0 +1,3 @@
+#import <Foundation/Foundation.h>
+
+extern NSString * const SpaceShipNotification;

test/Interop/Cxx/objc-correctness/nsnotification-bridging-ide-test.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=NSNofiticationBridging -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop -enable-objc-interop | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+// CHECK: @_exported import Foundation
+
+// CHECK: @available(swift, obsoleted: 3, renamed: "NSNotification.Name.SpaceShip")
+// CHECK: let SpaceShipNotification: NSNotification.Name