llvm/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.unused/p1.cpp

// RUN: %clang_cc1 -fsyntax-only -Wunused -std=c++1z -verify %s

struct [[maybe_unused]] S1 {}; // ok
struct [[maybe_unused, maybe_unused]] S2 {}; // ok
struct [[maybe_unused("Wrong")]] S3 {}; // expected-error {{'maybe_unused' cannot have an argument list}}