clang/test/SemaCXX/attribute-pack-expansion.cpp

   1 // RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s
   2
   3 template <bool... vals>
   4 void f() __attribute((diagnose_if(vals, "message", "error"))) { // expected-error {{expression contains unexpanded parameter pack 'vals'}}
   5   [] () __attribute((diagnose_if(vals, "message", "error"))) {}(); // expected-error {{expression contains unexpanded parameter pack 'vals'}}
   6   [] () __attribute((diagnose_if(vals..., "message", "error"))) {}(); // expected-error {{attribute 'diagnose_if' does not support argument pack expansion}}
   7   [] <bool ...inner> () __attribute((diagnose_if(inner, "message", "error"))) {}(); // expected-error {{expression contains unexpanded parameter pack 'inner'}}
   8   ([] <bool ...inner> () __attribute((diagnose_if(inner, "message", "error"))) {}(), ...); // expected-error {{expression contains unexpanded parameter pack 'inner'}} \
   9                                                                                            // expected-error {{pack expansion does not contain any unexpanded parameter packs}}
  10
  11   // This is fine, so check that we're actually emitting an error
  12   // due to the 'diagnose_if'.
  13   ([] () __attribute((diagnose_if(vals, "foobar", "error"))) {}(), ...); // expected-error {{foobar}} expected-note {{from 'diagnose_if'}}
  14 }
  15
  16 void g() {
  17   f<>();
  18   f<false>();
  19   f<true, true>(); // expected-note {{in instantiation of}}
  20 }