diff --git a/unittests/IR/ValueMapTest.cpp b/unittests/IR/ValueMapTest.cpp
index 5aaf9058362..cc844ba30b0 100644
--- a/unittests/IR/ValueMapTest.cpp
+++ b/unittests/IR/ValueMapTest.cpp
@@ -117,7 +117,8 @@ TYPED_TEST(ValueMapTest, OperationsWork) {
 
 template<typename ExpectedType, typename VarType>
 void CompileAssertHasType(VarType) {
-  typedef char assert[is_same<ExpectedType, VarType>::value ? 1 : -1];
+  LLVM_ATTRIBUTE_UNUSED typedef char
+  assert[is_same<ExpectedType, VarType>::value ? 1 : -1];
 }
 
 TYPED_TEST(ValueMapTest, Iteration) {