clang/test/SemaCXX/libstdcxx_pair_swap_hack.cpp

   1 // This is a test for an egregious hack in Clang that works around
   2 // an issue with GCC's <utility> implementation. std::pair::swap
   3 // has an exception specification that makes an unqualified call to
   4 // swap. This is invalid, because it ends up calling itself with
   5 // the wrong number of arguments.
   6 //
   7 // The same problem afflicts a bunch of other class templates. Those
   8 // affected are array, pair, priority_queue, stack, and queue.
   9
  10 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=array
  11 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=array -DPR28423
  12 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=pair
  13 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=priority_queue
  14 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=stack
  15 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=queue
  16 //
  17 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=array -DNAMESPACE=__debug
  18 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=array -DNAMESPACE=__profile
  19
  20 // MSVC's standard library uses a very similar pattern that relies on delayed
  21 // parsing of exception specifications.
  22 //
  23 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify -fexceptions -fcxx-exceptions -DCLASS=array -DMSVC
  24
  25 #ifdef BE_THE_HEADER
  26
  27 #pragma GCC system_header
  28 #ifdef PR28423
  29 using namespace std;
  30 #endif
  31
  32 namespace std {
  33   template<typename T> void swap(T &, T &);
  34   template<typename T> void do_swap(T &a, T &b) noexcept(noexcept(swap(a, b))) {
  35     swap(a, b);
  36   }
  37
  38 #ifdef NAMESPACE
  39   namespace NAMESPACE {
  40 #define STD_CLASS std::NAMESPACE::CLASS
  41 #else
  42 #define STD_CLASS std::CLASS
  43 #endif
  44
  45   template<typename A, typename B> struct CLASS {
  46 #ifdef MSVC
  47     void swap(CLASS &other) noexcept(noexcept(do_swap(member, other.member)));
  48 #endif
  49     A member;
  50 #ifndef MSVC
  51     void swap(CLASS &other) noexcept(noexcept(swap(member, other.member)));
  52 #endif
  53   };
  54
  55 //  template<typename T> void do_swap(T &, T &);
  56 //  template<typename A> struct vector {
  57 //    void swap(vector &other) noexcept(noexcept(do_swap(member, other.member)));
  58 //    A member;
  59 //  };
  60
  61 #ifdef NAMESPACE
  62   }
  63 #endif
  64 }
  65
  66 #else
  67
  68 #define BE_THE_HEADER
  69 #include __FILE__
  70
  71 struct X {};
  72 using PX = STD_CLASS<X, X>;
  73 using PI = STD_CLASS<int, int>;
  74 void swap(X &, X &) noexcept;
  75 PX px;
  76 PI pi;
  77
  78 static_assert(noexcept(px.swap(px)), "");
  79 static_assert(!noexcept(pi.swap(pi)), "");
  80
  81 namespace sad {
  82   template<typename T> void swap(T &, T &);
  83
  84   template<typename A, typename B> struct CLASS {
  85     void swap(CLASS &other) noexcept(noexcept(swap(*this, other))); // expected-error {{too many arguments}} expected-note {{declared here}}
  86     // expected-error@-1{{uses itself}} expected-note@-1{{in instantiation of}}
  87   };
  88
  89   CLASS<int, int> pi;
  90
  91   static_assert(!noexcept(pi.swap(pi)), ""); // expected-note 2{{in instantiation of exception specification for 'swap'}}
  92 }
  93
  94 #endif