diff --git a/test/tint/loops/while.wgsl.expected.msl b/test/tint/loops/while.wgsl.expected.msl
index f7428f9..d044fb0 100644
--- a/test/tint/loops/while.wgsl.expected.msl
+++ b/test/tint/loops/while.wgsl.expected.msl
@@ -2,12 +2,13 @@
 
 using namespace metal;
 
-#define TINT_ISOLATE_UB \
-  if (volatile bool tint_volatile_true = true; tint_volatile_true)
+#define TINT_ISOLATE_UB(VOLATILE_NAME) \
+  volatile bool VOLATILE_NAME = true; \
+  if (VOLATILE_NAME)
 
 int f() {
   int i = 0;
-  TINT_ISOLATE_UB while((i < 4)) {
+  TINT_ISOLATE_UB(tint_volatile_true) while((i < 4)) {
     i = as_type<int>((as_type<uint>(i) + as_type<uint>(1)));
   }
   return i;