clang/test/Parser/decomposed-condition.cpp

   1 // RUN: %clang_cc1 -std=c++1z %s -verify
   2
   3 namespace std {
   4   template<typename> struct tuple_size;
   5   template<int, typename> struct tuple_element;
   6 }
   7
   8 struct Get {
   9   template<int> int get() { return 0; }
  10   operator bool() { return true; }
  11 };
  12
  13 namespace std {
  14   template<> struct tuple_size<Get> { static constexpr int value = 1; };
  15   template<> struct tuple_element<0, Get> { using type = int; };
  16 }
  17
  18 struct Na {
  19   bool flag;
  20   float data;
  21 };
  22
  23 struct Rst {
  24   bool flag;
  25   float data;
  26   explicit operator bool() const {
  27     return flag;
  28   }
  29 };
  30
  31 Rst f();
  32 Na g();
  33
  34 namespace CondInIf {
  35 int h() {
  36   if (auto [ok, d] = f()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  37     ;
  38   if (auto [ok, d] = g()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}} expected-error {{value of type 'Na' is not contextually convertible to 'bool'}}
  39     ;
  40   if (auto [value] = Get()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  41     return value;
  42 }
  43 } // namespace CondInIf
  44
  45 namespace CondInWhile {
  46 int h() {
  47   while (auto [ok, d] = f()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  48     ;
  49   while (auto [ok, d] = g()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}} expected-error {{value of type 'Na' is not contextually convertible to 'bool'}}
  50     ;
  51   while (auto [value] = Get()) // expected-warning{{ISO C++17 does not permit structured binding declaration in a condition}}
  52     return value;
  53 }
  54 } // namespace CondInWhile
  55
  56 namespace CondInFor {
  57 int h() {
  58   for (; auto [ok, d] = f();) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  59     ;
  60   for (; auto [ok, d] = g();) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}} expected-error {{value of type 'Na' is not contextually convertible to 'bool'}}
  61     ;
  62   for (; auto [value] = Get();) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  63     return value;
  64 }
  65 } // namespace CondInFor
  66
  67 struct IntegerLike {
  68   bool flag;
  69   float data;
  70   operator int() const {
  71     return int(data);
  72   }
  73 };
  74
  75 namespace CondInSwitch {
  76 int h(IntegerLike x) {
  77   switch (auto [ok, d] = x) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  78     ;
  79   switch (auto [ok, d] = g()) // expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}} expected-error {{statement requires expression of integer type ('Na' invalid)}}
  80     ;
  81   switch (auto [value] = Get()) {// expected-warning {{ISO C++17 does not permit structured binding declaration in a condition}}
  82   // expected-warning@-1{{switch condition has boolean value}}
  83   case 1:
  84     return value;
  85   }
  86 }
  87 } // namespace CondInSwitch