clang/test/SemaCXX/cxx17-compat.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++17 -pedantic -verify %s
   2 // RUN: %clang_cc1 -fsyntax-only -std=c++20 -Wc++17-compat-pedantic -verify %s -Wno-defaulted-function-deleted
   3
   4 struct A {};
   5 int (A::*pa)() const&;
   6 int use_pa = (A().*pa)();
   7 #if __cplusplus <= 201703L
   8   // expected-warning@-2 {{invoking a pointer to a 'const &' member function on an rvalue is a C++20 extension}}
   9 #else
  10   // expected-warning@-4 {{invoking a pointer to a 'const &' member function on an rvalue is incompatible with C++ standards before C++20}}
  11 #endif
  12
  13 struct B {
  14   void b() {
  15     (void) [=, this] {};
  16 #if __cplusplus <= 201703L
  17     // expected-warning@-2 {{explicit capture of 'this' with a capture default of '=' is a C++20 extension}}
  18 #else
  19     // expected-warning@-4 {{explicit capture of 'this' with a capture default of '=' is incompatible with C++ standards before C++20}}
  20 #endif
  21   }
  22
  23   int n : 5 = 0;
  24 #if __cplusplus <= 201703L
  25     // expected-warning@-2 {{default member initializer for bit-field is a C++20 extension}}
  26 #else
  27     // expected-warning@-4 {{default member initializer for bit-field is incompatible with C++ standards before C++20}}
  28 #endif
  29 };
  30
  31 auto Lambda = []{};
  32 decltype(Lambda) AnotherLambda;
  33 #if __cplusplus <= 201703L
  34     // expected-error@-2 {{no matching constructor}} expected-note@-3 2{{candidate}}
  35 #else
  36     // expected-warning@-4 {{default construction of lambda is incompatible with C++ standards before C++20}}
  37 #endif
  38
  39 void copy_lambda() { Lambda = Lambda; }
  40 #if __cplusplus <= 201703L
  41     // expected-error@-2 {{deleted}} expected-note@-10 {{lambda}}
  42 #else
  43     // expected-warning@-4 {{assignment of lambda is incompatible with C++ standards before C++20}}
  44 #endif
  45
  46 struct DefaultDeleteWrongTypeBase {
  47   DefaultDeleteWrongTypeBase(DefaultDeleteWrongTypeBase&);
  48 };
  49 struct DefaultDeleteWrongType : DefaultDeleteWrongTypeBase {
  50   DefaultDeleteWrongType(const DefaultDeleteWrongType&) = default;
  51 #if __cplusplus <= 201703L
  52     // expected-error@-2 {{a member or base requires it to be non-const}}
  53 #else
  54     // expected-warning@-4 {{explicitly defaulting this copy constructor with a type different from the implicit type is incompatible with C++ standards before C++20}}
  55 #endif
  56 };
  57
  58 void ForRangeInit() {
  59   for (int arr[3] = {1, 2, 3}; int n : arr) {}
  60 #if __cplusplus <= 201703L
  61     // expected-warning@-2 {{range-based for loop initialization statements are a C++20 extension}}
  62 #else
  63     // expected-warning@-4 {{range-based for loop initialization statements are incompatible with C++ standards before C++20}}
  64 #endif
  65 }
  66
  67 struct ConstexprVirtual {
  68   virtual constexpr void f() {}
  69 #if __cplusplus <= 201703L
  70     // expected-error@-2 {{virtual function cannot be constexpr}}
  71 #else
  72     // expected-warning@-4 {{virtual constexpr functions are incompatible with C++ standards before C++20}}
  73 #endif
  74 };
  75
  76 struct C { int x, y, z; };
  77 static auto [cx, cy, cz] = C();
  78 #if __cplusplus <= 201703L
  79     // expected-warning@-2 {{decomposition declaration declared 'static' is a C++20 extension}}
  80 #else
  81     // expected-warning@-4 {{decomposition declaration declared 'static' is incompatible with C++ standards before C++20}}
  82 #endif
  83 void f() {
  84   static thread_local auto [cx, cy, cz] = C();
  85 #if __cplusplus <= 201703L
  86     // expected-warning@-2 {{decomposition declaration declared with 'static thread_local' specifiers is a C++20 extension}}
  87 #else
  88     // expected-warning@-4 {{decomposition declaration declared with 'static thread_local' specifiers is incompatible with C++ standards before C++20}}
  89 #endif
  90 }
  91
  92 struct DefaultedComparisons {
  93   bool operator==(const DefaultedComparisons&) const = default;
  94   bool operator!=(const DefaultedComparisons&) const = default;
  95 #if __cplusplus <= 201703L
  96   // expected-warning@-3 {{defaulted comparison operators are a C++20 extension}}
  97   // expected-warning@-3 {{defaulted comparison operators are a C++20 extension}}
  98 #else
  99   // expected-warning@-6 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 100   // expected-warning@-6 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 101 #endif
 102   bool operator<=>(const DefaultedComparisons&) const = default;
 103 #if __cplusplus <= 201703L
 104   // expected-error@-2 {{'operator<=' cannot be the name of a variable or data member}} expected-error@-2 0+{{}} expected-warning@-2 {{}}
 105 #else
 106   // expected-warning@-4 {{'<=>' operator is incompatible with C++ standards before C++20}}
 107 #endif
 108   bool operator<(const DefaultedComparisons&) const = default;
 109   bool operator<=(const DefaultedComparisons&) const = default;
 110   bool operator>(const DefaultedComparisons&) const = default;
 111   bool operator>=(const DefaultedComparisons&) const = default;
 112 #if __cplusplus <= 201703L
 113   // expected-error@-5 {{only special member functions}}
 114   // expected-error@-5 {{only special member functions}}
 115   // expected-error@-5 {{only special member functions}}
 116   // expected-error@-5 {{only special member functions}}
 117 #else
 118   // expected-warning@-10 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 119   // expected-warning@-10 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 120   // expected-warning@-10 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 121   // expected-warning@-10 {{defaulted comparison operators are incompatible with C++ standards before C++20}}
 122 #endif
 123 };
 124
 125 namespace NTTP {
 126   struct A {};
 127   template<A> struct Class {};
 128 #if __cplusplus <= 201703L
 129   // expected-error@-2 {{non-type template parameter cannot have type 'NTTP::A' before C++20}}
 130 #else
 131   // expected-warning@-4 {{non-type template parameter of type 'NTTP::A' is incompatible with C++ standards before C++20}}
 132 #endif
 133 }