diff --git a/clang/unittests/AST/UnresolvedSetTest.cpp b/clang/unittests/AST/UnresolvedSetTest.cpp
index 147c42e1fb088..ada857e0e3826 100644
--- a/clang/unittests/AST/UnresolvedSetTest.cpp
+++ b/clang/unittests/AST/UnresolvedSetTest.cpp
@@ -5,7 +5,7 @@ namespace clang {
 class NamedDecl {
   // DeclAccessPair assumes that NamedDecl is at least 4-byte aligned, so we
   // we need to have a dummy value to make this dummy NamedDecl also be aligned.
-  int dummy __attribute__((unused));
+  [[maybe_unused]] int dummy;
 
 public:
   NamedDecl() {}