diff --git a/libcxx/test/support/nasty_macros.h b/libcxx/test/support/nasty_macros.h
index 9dab4f84ea1996..9aa496bd02e5fe 100644
--- a/libcxx/test/support/nasty_macros.h
+++ b/libcxx/test/support/nasty_macros.h
@@ -64,7 +64,6 @@
 #define __opt NASTY_MACRO
 #define __out NASTY_MACRO
 #define __part NASTY_MACRO
-#define __z NASTY_MACRO
 #endif
 
 #define __output NASTY_MACRO