clang/test/SemaCXX/libstdcxx_is_pod_hack.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %std_cxx98-14 %s
   2
   3 // This is a test for an egregious hack in Clang that works around
   4 // issues with GCC's evolution. libstdc++ 4.2.x uses __is_pod as an
   5 // identifier (to declare a struct template like the one below), while
   6 // GCC 4.3 and newer make __is_pod a keyword. Clang treats __is_pod as
   7 // a keyword *unless* it is introduced following the struct keyword.
   8
   9 template<typename T>
  10 struct __is_pod { // expected-warning {{keyword '__is_pod' will be made available as an identifier}}
  11   __is_pod() {}
  12 };
  13
  14 __is_pod<int> ipi;
  15
  16 // Ditto for __is_same.
  17 template<typename T>
  18 struct __is_same { // expected-warning {{keyword '__is_same' will be made available as an identifier}}
  19 };
  20
  21 __is_same<int> isi;
  22
  23 // Another, similar egregious hack for __is_signed, which is a type
  24 // trait in Embarcadero's compiler but is used as an identifier in
  25 // libstdc++.
  26 struct test_is_signed {
  27   static const bool __is_signed = true; // expected-warning {{keyword '__is_signed' will be made available as an identifier}}
  28 };
  29
  30 bool check_signed = test_is_signed::__is_signed;
  31
  32 template<bool B> struct must_be_true {};
  33 template<> struct must_be_true<false>;
  34
  35 void foo() {
  36   bool b = __is_pod(int);
  37   must_be_true<__is_pod(int)> mbt;
  38 }
  39
  40 // expected-warning@+1 {{declaration does not declare anything}}
  41 struct // expected-error {{declaration of anonymous struct must be a definition}}
  42 #pragma pack(pop)
  43     S {
  44 };
  45
  46 #if !__has_feature(is_pod)
  47 #  error __is_pod should still be available.
  48 #endif