diff --git a/clang/test/Modules/Inputs/system-out-of-date/X.h b/clang/test/Modules/Inputs/system-out-of-date/X.h
index edcfa18f5af5..f26ce7e27d09 100644
--- a/clang/test/Modules/Inputs/system-out-of-date/X.h
+++ b/clang/test/Modules/Inputs/system-out-of-date/X.h
@@ -1 +1,2 @@
+// X.h
 #import <Y.h>
diff --git a/clang/test/Modules/Inputs/system-out-of-date/Z.h b/clang/test/Modules/Inputs/system-out-of-date/Z.h
index edcfa18f5af5..5db801a509de 100644
--- a/clang/test/Modules/Inputs/system-out-of-date/Z.h
+++ b/clang/test/Modules/Inputs/system-out-of-date/Z.h
@@ -1 +1,2 @@
+// Z.h
 #import <Y.h>