diff --git a/stdlib/public/stubs/FoundationHelpers.mm b/stdlib/public/stubs/FoundationHelpers.mm
index 2a406098220a8..6a086354fc94a 100644
--- a/stdlib/public/stubs/FoundationHelpers.mm
+++ b/stdlib/public/stubs/FoundationHelpers.mm
@@ -109,6 +109,6 @@ static CFRange cast(_swift_shims_CFRange value) {
 }
 
 _swift_shims_CFStringRef
-swift::_swift_stdlib_objcDebugDescription(id __nonnull nsObject) {
+swift::_swift_stdlib_objcDebugDescription(id _Nonnull nsObject) {
   return [nsObject debugDescription];
 }