diff --git a/src/corelib/global/qflags.h b/src/corelib/global/qflags.h
index a23dbb53cd..92bcb0df9c 100644
--- a/src/corelib/global/qflags.h
+++ b/src/corelib/global/qflags.h
@@ -218,6 +218,7 @@ QT_DECLARE_TYPESAFE_OPERATORS_FOR_FLAGS_ENUM(Flags)
 #if __cplusplus > 201702L // assume compilers don't warn if in C++17 mode
   // in C++20 mode, provide user-defined operators to override the deprecated operations:
 # define Q_DECLARE_MIXED_ENUM_OPERATOR(op, Ret, LHS, RHS) \
+    [[maybe_unused]] \
     constexpr inline Ret operator op (LHS lhs, RHS rhs) noexcept \
     { return static_cast<Ret>(qToUnderlying(lhs) op qToUnderlying(rhs)); } \
     /* end */