xref: /llvm-project/clang/test/CXX/drs/cwg2xx.cpp (revision 10fb5d2b4be54c779eda80b65a737b9dae2d959b)

// RUN: %clang_cc1 -std=c++98 %s -verify=expected,cxx98,cxx98-11,cxx98-14,cxx98-17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 %s -verify=expected,since-cxx11,cxx98-11,cxx98-14,cxx98-17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 %s -verify=expected,since-cxx11,since-cxx14,cxx98-14,cxx98-17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++17 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,cxx98-17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++20 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++23 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++2c %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors

// FIXME: diagnostic above is emitted only on Windows platforms
// PR13819 -- __SIZE_TYPE__ is incompatible.
typedef __SIZE_TYPE__ size_t;
// cxx98-error@-1 0-1 {{'long long' is a C++11 extension}}

#if __cplusplus == 199711L
#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
// cxx98-error@-1 {{variadic macros are a C99 feature}}
#endif

#if __cplusplus == 199711L
#define __enable_constant_folding(x) (__builtin_constant_p(x) ? (x) : (x))
#else
#define __enable_constant_folding
#endif

namespace cwg200 { // cwg200: dup 214
  template <class T> T f(int);
  template <class T, class U> T f(U) = delete;
  // cxx98-error@-1 {{deleted function definitions are a C++11 extension}}

  void g() {
    f<int>(1);
  }
} // namespace cwg200

// cwg201 is in cwg201.cpp

namespace cwg202 { // cwg202: 3.1
  template<typename T> T f();
  template<int (*g)()> struct X {
    static_assert(__enable_constant_folding(g == &f<int>), "");
  };
  template struct X<f>;
} // namespace cwg202

namespace cwg203 { // cwg203: 3.0
namespace ex1 {
struct B {
  int i;
};
struct D1 : B {};
struct D2 : B {};

int(D1::*pmD1) = &D2::i;
} // namespace ex1

#if __cplusplus >= 202002L
namespace ex2 {
struct A {
  int i;
  virtual void f() = 0; // #cwg203-ex2-A-f
};

struct B : A {
  int j;
  constexpr B() : j(5) {}
  virtual void f();
};

struct C : B {
  constexpr C() { j = 10; }
};

template <class T>
constexpr int DefaultValue(int(T::*m)) {
  return T().*m;
  // since-cxx20-error@-1 {{allocating an object of abstract class type 'cwg203::ex2::A'}}
  //   since-cxx20-note@#cwg203-ex2-a {{in instantiation of function template specialization 'cwg203::ex2::DefaultValue<cwg203::ex2::A>' requested here}}
  //   since-cxx20-note@#cwg203-ex2-A-f {{unimplemented pure virtual method 'f' in 'A'}}
} // #cwg203-ex2-DefaultValue

int a = DefaultValue(&B::i); // #cwg203-ex2-a
static_assert(DefaultValue(&C::j) == 5, "");
} // namespace ex2
#endif

namespace ex3 {
class Base {
public:
  int func() const;
};

class Derived : public Base {};

template <class T> class Templ { // #cwg203-ex3-Templ
public:
  template <class S> Templ(S (T::*ptmf)() const); // #cwg203-ex3-Templ-ctor
};

void foo() { Templ<Derived> x(&Derived::func); }
// expected-error@-1 {{no matching constructor for initialization of 'Templ<Derived>'}}
//   expected-note@#cwg203-ex3-Templ {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int (cwg203::ex3::Base::*)() const' to 'const Templ<Derived>' for 1st argument}}
//   since-cxx11-note@#cwg203-ex3-Templ {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int (cwg203::ex3::Base::*)() const' to 'Templ<Derived>' for 1st argument}}
//   expected-note@#cwg203-ex3-Templ-ctor {{candidate template ignored: could not match 'cwg203::ex3::Derived' against 'cwg203::ex3::Base'}}
} // namespace ex3

namespace ex4 {
struct Very_base {
  int a;
};
struct Base1 : Very_base {};
struct Base2 : Very_base {};
struct Derived : Base1, Base2 {
};

int f() {
  Derived d;
  // FIXME: in the diagnostic below, Very_base is fully qualified, but Derived is not
  int Derived::*a_ptr = &Derived::Base1::a;
  /* expected-error@-1
  {{ambiguous conversion from pointer to member of base class 'cwg203::ex4::Very_base' to pointer to member of derived class 'Derived':
    struct cwg203::ex4::Derived -> Base1 -> Very_base
    struct cwg203::ex4::Derived -> Base2 -> Very_base}}*/
}
} // namespace ex4

namespace ex5 {
struct Base {
  int a;
};
struct Derived : Base {
  int b;
};

template <typename Class, typename Member_type, Member_type Base::*ptr>
Member_type get(Class &c) {
  return c.*ptr;
}

void call(int (*f)(Derived &)); // #cwg203-ex5-call

int f() {
  // ill-formed, contrary to Core issue filing:
  // `&Derived::b` yields `int Derived::*`, which can't initialize NTTP of type `int Base::*`,
  // because (implicit) pointer-to-member conversion doesn't upcast.
  call(&get<Derived, int, &Derived::b>);
  // expected-error@-1 {{no matching function for call to 'call'}}
  //   expected-note@#cwg203-ex5-call {{candidate function not viable: no overload of 'get' matching 'int (*)(Derived &)' for 1st argument}}

  // well-formed, contrary to Core issue filing:
  // `&Derived::a` yields `int Base::*`,
  // which can initialize NTTP of type `int Base::*`.
  call(&get<Derived, int, &Derived::a>);

  call(&get<Base, int, &Derived::a>);
  // expected-error@-1 {{no matching function for call to 'call'}}
  //   expected-note@#cwg203-ex5-call {{candidate function not viable: no overload of 'get' matching 'int (*)(Derived &)' for 1st argument}}
}
} // namespace ex5

namespace ex6 {
struct Base {
  int a;
};
struct Derived : private Base { // #cwg203-ex6-Derived
public:
  using Base::a; // make `a` accessible
};

int f() {
  Derived d;
  int b = d.a;
  // FIXME: in the diagnostic below, Base is fully qualified, but Derived is not
  int Derived::*ptr = &Derived::a;
  // expected-error@-1 {{cannot cast private base class 'cwg203::ex6::Base' to 'Derived'}}
  //   expected-note@#cwg203-ex6-Derived {{declared private here}}
}
} // namespace ex6
} // namespace cwg203

// cwg204: sup 820

namespace cwg206 { // cwg206: 2.7
  struct S; // #cwg206-S
  template<typename T> struct Q { S s; };
  // expected-error@-1 {{field has incomplete type 'S'}}
  //   expected-note@#cwg206-S {{forward declaration of 'cwg206::S'}}
  template<typename T> void f() { S s; }
  // expected-error@-1 {{variable has incomplete type 'S'}}
  //   expected-note@#cwg206-S {{forward declaration of 'cwg206::S'}}
} // namespace cwg206

namespace cwg207 { // cwg207: 2.7
  class A {
  protected:
    static void f() {}
  };
  class B : A {
  public:
    using A::f;
    void g() {
      A::f();
      f();
    }
  };
} // namespace cwg207

// cwg208 FIXME: write codegen test

namespace cwg209 { // cwg209: 3.2
  class A {
    void f(); // #cwg209-A-f
  };
  class B {
    friend void A::f();
    // expected-error@-1 {{friend function 'f' is a private member of 'cwg209::A'}}
    //   expected-note@#cwg209-A-f {{implicitly declared private here}}
  };
} // namespace cwg209

// cwg210 is in cwg210.cpp

namespace cwg211 { // cwg211: 2.7
  struct A {
    A() try {
      throw 0;
    } catch (...) {
      return;
      // expected-error@-1 {{return in the catch of a function try block of a constructor is illegal}}
    }
  };
} // namespace cwg211

namespace cwg213 { // cwg213: 2.7
  template <class T> struct A : T {
    void h(T t) {
      char &r1 = f(t);
      int &r2 = g(t);
      // expected-error@-1 {{explicit qualification required to use member 'g' from dependent base class}}
      //   expected-note@#cwg213-instantiation {{in instantiation of member function 'cwg213::A<cwg213::B>::h' requested here}}
      //   expected-note@#cwg213-B-g {{member is declared here}}
    }
  };
  struct B {
    int &f(B);
    int &g(B); // #cwg213-B-g
  };
  char &f(B);

  template void A<B>::h(B); // #cwg213-instantiation
} // namespace cwg213

namespace cwg214 { // cwg214: 2.7
  template<typename T, typename U> T checked_cast(U from) { U::error; }
  template<typename T, typename U> T checked_cast(U *from);
  class C {};
  void foo(int *arg) { checked_cast<const C *>(arg); }

  template<typename T> T f(int);
  template<typename T, typename U> T f(U) { T::error; }
  void g() {
    f<int>(1);
  }
} // namespace cwg214

namespace cwg215 { // cwg215: 2.9
  template<typename T> class X {
    friend void T::foo();
    int n;
  };
  struct Y {
    void foo() { (void)+X<Y>().n; }
  };
} // namespace cwg215

namespace cwg216 { // cwg216: no
  // FIXME: Should reject this: 'f' has linkage but its type does not,
  // and 'f' is odr-used but not defined in this TU.
  typedef enum { e } *E;
  void f(E);
  void g(E e) { f(e); }

  struct S {
    // FIXME: Should reject this: 'f' has linkage but its type does not,
    // and 'f' is odr-used but not defined in this TU.
    typedef enum { e } *E;
    void f(E);
  };
  void g(S s, S::E e) { s.f(e); }
} // namespace cwg216

namespace cwg217 { // cwg217: 2.7
  template<typename T> struct S {
    void f(int);
  };
  template<typename T> void S<T>::f(int = 0) {}
  // expected-error@-1 {{default arguments cannot be added to an out-of-line definition of a member of a class template}}
} // namespace cwg217

namespace cwg218 { // cwg218: 2.7
                  // NB: also dup 405
  namespace A {
    struct S {};
    void f(S);
  }
  namespace B {
    struct S {};
    void f(S);
  }

  struct C {
    int f;
    void test1(A::S as) { f(as); }
    // expected-error@-1 {{called object type 'int' is not a function or function pointer}}
    void test2(A::S as) { void f(); f(as); }
    // expected-error@-1 {{too many arguments to function call, expected 0, have 1}}
    //   expected-note@-2 {{'f' declared here}}
    void test3(A::S as) { using A::f; f(as); } // ok
    void test4(A::S as) { using B::f; f(as); } // ok
    void test5(A::S as) { int f; f(as); }
    // expected-error@-1 {{called object type 'int' is not a function or function pointer}}
    void test6(A::S as) { struct f {}; (void) f(as); }
    // expected-error@-1 {{no matching conversion for functional-style cast from 'A::S' to 'f'}}
    //   expected-note@-2 {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'A::S' to 'const f' for 1st argument}}
    //   since-cxx11-note@-3 {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'A::S' to 'f' for 1st argument}}
    //   expected-note@-4 {{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
  };

  namespace D {
    struct S {};
    struct X { void operator()(S); } f;
  }
  void testD(D::S ds) { f(ds); }
  // expected-error@-1 {{use of undeclared identifier 'f'}}

  namespace E {
    struct S {};
    struct f { f(S); };
  }
  void testE(E::S es) { f(es); }
  // expected-error@-1 {{use of undeclared identifier 'f'}}

  namespace F {
    struct S {
      template<typename T> friend void f(S, T) {}
    };
  }
  void testF(F::S fs) { f(fs, 0); }

  namespace G {
    namespace X {
      int f;
      struct A {};
    }
    namespace Y {
      template<typename T> void f(T);
      struct B {};
    }
    template<typename A, typename B> struct C {};
  }
  void testG(G::C<G::X::A, G::Y::B> gc) { f(gc); }
} // namespace cwg218

// cwg219: na
// cwg220: na

namespace cwg221 { // cwg221: 3.6
  struct A { // #cwg221-S
    A &operator=(int&); // #cwg221-S-copy-assign
    A &operator+=(int&);
    static A &operator=(A&, double&);
    // expected-error@-1 {{overloaded 'operator=' cannot be a static member function}}
    static A &operator+=(A&, double&);
    // expected-error@-1 {{overloaded 'operator+=' cannot be a static member function}}
    friend A &operator=(A&, char&);
    // expected-error@-1 {{overloaded 'operator=' must be a non-static member function}}
    friend A &operator+=(A&, char&);
  };
  A &operator=(A&, float&);
  // expected-error@-1 {{overloaded 'operator=' must be a non-static member function}}
  A &operator+=(A&, float&);

  void test(A a, int n, char c, float f) {
    a = n;
    a += n;
    a = c;
    // expected-error@-1 {{no viable overloaded '='}}
    //   expected-note@#cwg221-S-copy-assign {{candidate function not viable: no known conversion from 'char' to 'int &' for 1st argument}}
    //   since-cxx11-note@#cwg221-S {{candidate function (the implicit move assignment operator) not viable: no known conversion from 'char' to 'A' for 1st argument}}
    //   expected-note@#cwg221-S {{candidate function (the implicit copy assignment operator) not viable: no known conversion from 'char' to 'const A' for 1st argument}}
    a += c;
    a = f;
    // expected-error@-1 {{no viable overloaded '='}}
    //   expected-note@#cwg221-S-copy-assign {{candidate function not viable: no known conversion from 'float' to 'int &' for 1st argument}}
    //   since-cxx11-note@#cwg221-S {{candidate function (the implicit move assignment operator) not viable: no known conversion from 'float' to 'A' for 1st argument}}
    //   expected-note@#cwg221-S {{candidate function (the implicit copy assignment operator) not viable: no known conversion from 'float' to 'const A' for 1st argument}}
    a += f;
  }
} // namespace cwg221

namespace cwg222 { // cwg222: dup 637
  void f(int a, int b, int c, int *x) {
#pragma clang diagnostic push
#pragma clang diagnostic warning "-Wunsequenced"
    void((a += b) += c);
    void((a += b) + (a += c));
    // expected-warning@-1 {{multiple unsequenced modifications to 'a'}}

    x[a++] = a;
    // cxx98-14-warning@-1 {{unsequenced modification and access to 'a'}}

    a = b = 0; // ok, read and write of 'b' are sequenced

    a = (b = a++);
    // cxx98-14-warning@-1 {{multiple unsequenced modifications to 'a'}}
    a = (b = ++a);
#pragma clang diagnostic pop
  }
} // namespace cwg222

// cwg223: na

namespace cwg224 { // cwg224: 16
  namespace example1 {
    template <class T> class A {
      typedef int type;
      A::type a;
      A<T>::type b;
      A<T*>::type c;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name A<T *>::type; implicit 'typename' is a C++20 extension}}
      ::cwg224::example1::A<T>::type d;

      class B {
        typedef int type;

        A::type a;
        A<T>::type b;
        A<T*>::type c;
        // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name A<T *>::type; implicit 'typename' is a C++20 extension}}
        ::cwg224::example1::A<T>::type d;

        B::type e;
        A<T>::B::type f;
        A<T*>::B::type g;
        // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name A<T *>::B::type; implicit 'typename' is a C++20 extension}}
        typename A<T*>::B::type h;
      };
    };

    template <class T> class A<T*> {
      typedef int type;
      A<T*>::type a;
      A<T>::type b;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name A<T>::type; implicit 'typename' is a C++20 extension}}
    };

    template <class T1, class T2, int I> struct B {
      typedef int type;
      B<T1, T2, I>::type b1;
      B<T2, T1, I>::type b2;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name B<T2, T1, I>::type; implicit 'typename' is a C++20 extension}}

      typedef T1 my_T1;
      static const int my_I = I;
      static const int my_I2 = I+0;
      static const int my_I3 = my_I;
      B<my_T1, T2, my_I>::type b3;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name B<my_T1, T2, my_I>::type; implicit 'typename' is a C++20 extension}}
      B<my_T1, T2, my_I2>::type b4;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name B<my_T1, T2, my_I2>::type; implicit 'typename' is a C++20 extension}}
      B<my_T1, T2, my_I3>::type b5;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name B<my_T1, T2, my_I3>::type; implicit 'typename' is a C++20 extension}}
    };
  }

  namespace example2 {
    template <int, typename T> struct X { typedef T type; };
    template <class T> class A {
      static const int i = 5;
      X<i, int>::type w;
      X<A::i, char>::type x;
      X<A<T>::i, double>::type y;
      X<A<T*>::i, long>::type z;
      // cxx98-17-error@-1 {{missing 'typename' prior to dependent type name X<A<T *>::i, long>::type; implicit 'typename' is a C++20 extension}}
      int f();
    };
    template <class T> int A<T>::f() {
      return i;
    }
  }
} // namespace cwg224

// cwg225: yes
template<typename T> void cwg225_f(T t) { cwg225_g(t); }
// expected-error@-1 {{call to function 'cwg225_g' that is neither visible in the template definition nor found by argument-dependent lookup}}
//   expected-note@#cwg225-f {{in instantiation of function template specialization 'cwg225_f<int>' requested here}}
//   expected-note@#cwg225-g {{'cwg225_g' should be declared prior to the call site}}
void cwg225_g(int); // #cwg225-g
template void cwg225_f(int); // #cwg225-f

namespace cwg226 { // cwg226: no
  // FIXME: This appears to be wrong: default arguments for function templates
  // are listed as a defect (in c++98) not an extension. EDG accepts them in
  // strict c++98 mode.
  template<typename T = void> void f() {}
  // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  template<typename T> struct S {
    template<typename U = void> void g();
    // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
    template<typename U> struct X;
    template<typename U> void h();
  };
  template<typename T> template<typename U> void S<T>::g() {}
  template<typename T> template<typename U = void> struct S<T>::X {};
  // expected-error@-1 {{cannot add a default template argument to the definition of a member of a class template}}
  template<typename T> template<typename U = void> void S<T>::h() {}
  // expected-error@-1 {{cannot add a default template argument to the definition of a member of a class template}}

  template<typename> void friend_h();
  struct A {
    // FIXME: This is ill-formed.
    template<typename=void> struct friend_B;
    // FIXME: f, h, and i are ill-formed.
    //  f is ill-formed because it is not a definition.
    //  h and i are ill-formed because they are not the only declarations of the
    //  function in the translation unit.
    template<typename=void> void friend_f();
    // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
    template<typename=void> void friend_g() {}
    // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
    template<typename=void> void friend_h() {}
    // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
    template<typename=void> void friend_i() {}
    // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  };
  template<typename> void friend_i();

  template<typename=void, typename X> void foo(X) {}
  // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  template<typename=void, typename X> struct Foo {};
  // expected-error@-1 {{template parameter missing a default argument}}
  //   expected-note@-2 {{previous default template argument defined here}}

  template<typename=void, typename X, typename, typename Y> int foo(X, Y);
  // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  template<typename, typename X, typename=void, typename Y> int foo(X, Y);
  // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  int x = foo(0, 0);
} // namespace cwg226

namespace cwg227 { // cwg227: 2.7
void f(bool b) {
  if (b)
    int n;
  else
    int n;
}
} // namespace cwg227

namespace cwg228 { // cwg228: 2.7
  template <class T> struct X {
    void f();
  };
  template <class T> struct Y {
    void g(X<T> x) { x.template X<T>::f(); }
  };
} // namespace cwg228

namespace cwg229 { // cwg229: 2.9
  template<typename T> void f();
  template<typename T> void f<T*>() {}
  // expected-error@-1 {{function template partial specialization is not allowed}}
  template<> void f<int>() {}
} // namespace cwg229

namespace cwg230 { // cwg230: 3.0
  struct S {
    S() { f(); }
    // expected-warning@-1 {{call to pure virtual member function 'f' has undefined behavior; overrides of 'f' in subclasses are not available in the constructor of 'cwg230::S'}}
    //   expected-note@#cwg230-f {{'f' declared here}}
    virtual void f() = 0; // #cwg230-f
  };
} // namespace cwg230

namespace cwg231 { // cwg231: 2.7
  namespace outer {
    namespace inner {
      int i; // #cwg231-i
    }
    void f() { using namespace inner; }
    int j = i;
    // expected-error@-1 {{use of undeclared identifier 'i'; did you mean 'inner::i'?}}
    //   expected-note@#cwg231-i {{'inner::i' declared here}}
  }
} // namespace cwg231

// cwg234: na
// cwg235: na

namespace cwg236 { // cwg236: 3.2
  void *p = int();
  // cxx98-warning@-1 {{expression which evaluates to zero treated as a null pointer constant of type 'void *'}}
  // since-cxx11-error@-2 {{cannot initialize a variable of type 'void *' with an rvalue of type 'int'}}
} // namespace cwg236

namespace cwg237 { // cwg237: dup 470
  template<typename T> struct A { void f() { T::error; } };
  template<typename T> struct B : A<T> {};
  template struct B<int>; // ok
} // namespace cwg237

namespace cwg239 { // cwg239: 2.7
  namespace NS {
    class T {};
    void f(T);
    float &g(T, int);
  }
  NS::T parm;
  int &g(NS::T, float);
  int main() {
    f(parm);
    float &r = g(parm, 1);
    extern int &g(NS::T, float);
    int &s = g(parm, 1);
  }
} // namespace cwg239

// cwg240: dup 616

namespace cwg241 { // cwg241: 9
  namespace A {
    struct B {};
    template <int X> void f(); // #cwg241-A-f
    template <int X> void g(B);
  }
  namespace C {
    template <class T> void f(T t); // #cwg241-C-f
    template <class T> void g(T t); // #cwg241-C-g
  }
  void h(A::B b) {
    f<3>(b);
    // expected-error@-1 {{no matching function for call to 'f'}}
    //   expected-note@#cwg241-A-f {{candidate function template not viable: requires 0 arguments, but 1 was provided}}
    // cxx98-17-error@-3 {{use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension}}
    g<3>(b);
    // cxx98-17-error@-1 {{use of function template name with no prior declaration in function call with explicit template arguments is a C++20 extension}}
    A::f<3>(b);
    // expected-error@-1 {{no matching function for call to 'f'}}
    //   expected-note@#cwg241-A-f {{candidate function template not viable: requires 0 arguments, but 1 was provided}}
    A::g<3>(b);
    C::f<3>(b);
    // expected-error@-1 {{no matching function for call to 'f'}}
    //   expected-note@#cwg241-C-f {{candidate template ignored: invalid explicitly-specified argument for template parameter 'T'}}
    C::g<3>(b);
    // expected-error@-1 {{no matching function for call to 'g'}}
    //   expected-note@#cwg241-C-g {{candidate template ignored: invalid explicitly-specified argument for template parameter 'T'}}
    using C::f;
    using C::g;
    f<3>(b);
    // expected-error@-1 {{no matching function for call to 'f'}}
    //   expected-note@#cwg241-C-f {{candidate template ignored: invalid explicitly-specified argument for template parameter 'T'}}
    //   expected-note@#cwg241-A-f {{candidate function template not viable: requires 0 arguments, but 1 was provided}}
    g<3>(b);
  }
} // namespace cwg241

namespace cwg243 { // cwg243: 2.8
  struct B;
  struct A {
    A(B); // #cwg243-A
  };
  struct B {
    operator A() = delete; // #cwg243-B
    // cxx98-error@-1 {{deleted function definitions are a C++11 extension}}
  } b;
  A a1(b);
  A a2 = b;
  // expected-error@-1 {{conversion from 'struct B' to 'A' is ambiguous}}
  //   expected-note@#cwg243-A {{candidate constructor}}
  //   expected-note@#cwg243-B {{candidate function has been explicitly deleted}}
} // namespace cwg243

namespace cwg244 { // cwg244: 11
                  // NB: this test is reused by cwg399
  struct B {}; // #cwg244-B
  struct D : B {};

  D D_object;
  typedef B B_alias;
  B* B_ptr = &D_object;

  void f() {
    D_object.~B();
    // expected-error@-1 {{destructor type 'cwg244::B' in object destruction expression does not match the type 'D' of the object being destroyed}}
    //   expected-note@#cwg244-B {{type 'cwg244::B' found by destructor name lookup}}
    D_object.B::~B();
    D_object.D::~B(); // FIXME: Missing diagnostic for this.
    B_ptr->~B();
    B_ptr->~B_alias();
    B_ptr->B_alias::~B();
    B_ptr->B_alias::~B_alias();
    B_ptr->cwg244::~B();
    // expected-error@-1 {{no member named '~B' in namespace 'cwg244'}}
    B_ptr->cwg244::~B_alias();
    // expected-error@-1 {{no member named '~B' in namespace 'cwg244'}}
  }

  template<typename T, typename U>
  void f(T *B_ptr, U D_object) {
    D_object.~B(); // FIXME: Missing diagnostic for this.
    D_object.B::~B();
    D_object.D::~B(); // FIXME: Missing diagnostic for this.
    B_ptr->~B();
    B_ptr->~B_alias();
    B_ptr->B_alias::~B();
    B_ptr->B_alias::~B_alias();
    B_ptr->cwg244::~B();
    // expected-error@-1 {{'cwg244' does not refer to a type name in pseudo-destructor expression; expected the name of type 'T'}}
    B_ptr->cwg244::~B_alias();
    // expected-error@-1 {{'cwg244' does not refer to a type name in pseudo-destructor expression; expected the name of type 'T'}}
  }
  template void f<B, D>(B*, D);

  namespace N {
    template<typename T> struct E {};
    typedef E<int> F;
  }
  void g(N::F f) {
    typedef N::F G; // #cwg244-G
    f.~G();
    f.G::~E();
    // expected-error@-1 {{ISO C++ requires the name after '::~' to be found in the same scope as the name before '::~'}}
    f.G::~F();
    // expected-error@-1 {{undeclared identifier 'F' in destructor name}}
    f.G::~G();
    // This is technically ill-formed; E is looked up in 'N::' and names the
    // class template, not the injected-class-name of the class. But that's
    // probably a bug in the standard.
    f.N::F::~E();
    // expected-error@-1 {{ISO C++ requires the name after '::~' to be found in the same scope as the name before '::~'}}
    // This is valid; we look up the second F in the same scope in which we
    // found the first one, that is, 'N::'.
    f.N::F::~F();
    // This is technically ill-formed; G is looked up in 'N::' and is not found.
    // Rejecting this seems correct, but most compilers accept, so we do also.
    f.N::F::~G();
    // expected-error@-1 {{qualified destructor name only found in lexical scope; omit the qualifier to find this type name by unqualified lookup}}
    //   expected-note@#cwg244-G {{type 'G' (aka 'E<int>') found by destructor name lookup}}
  }

  // Bizarrely, compilers perform lookup in the scope for qualified destructor
  // names, if the nested-name-specifier is non-dependent. Ensure we diagnose
  // this.
  namespace QualifiedLookupInScope {
    namespace N {
      template <typename> struct S { struct Inner {}; };
    }
    template <typename U> void f(typename N::S<U>::Inner *p) {
      typedef typename N::S<U>::Inner T;
      p->::cwg244::QualifiedLookupInScope::N::S<U>::Inner::~T();
      // expected-error@-1 {{no type named 'T' in 'cwg244::QualifiedLookupInScope::N::S<int>'}}
      //   expected-note@#cwg244-f {{in instantiation of function template specialization 'cwg244::QualifiedLookupInScope::f<int>' requested here}}
    }
    template void f<int>(N::S<int>::Inner *); // #cwg244-f

    template <typename U> void g(U *p) {
      typedef U T;
      p->T::~T();
      p->U::~T();
      p->::cwg244::QualifiedLookupInScope::N::S<int>::Inner::~T();
      // expected-error@-1 {{'T' does not refer to a type name in pseudo-destructor expression; expected the name of type 'U'}}
    }
    template void g(N::S<int>::Inner *);
  }
} // namespace cwg244

namespace cwg245 { // cwg245: 2.8
  struct S {
    enum E {}; // #cwg245-E
    class E *p;
    // expected-error@-1 {{use of 'E' with tag type that does not match previous declaration}}
    //   expected-note@#cwg245-E {{previous use is here}}
  };
} // namespace cwg245

namespace cwg246 { // cwg246: 3.2
  struct S {
    S() try { // #cwg246-try
      throw 0;
X: ;
    } catch (int) {
      goto X;
      // expected-error@-1 {{cannot jump from this goto statement to its label}}
      //   expected-note@#cwg246-try {{jump bypasses initialization of try block}}
    }
  };
} // namespace cwg246

namespace cwg247 { // cwg247: 2.7
  struct A {};
  struct B : A {
    void f();
    void f(int);
  };
  void (A::*f)() = (void (A::*)())&B::f;

  struct C {
    void f();
    void f(int);
  };
  struct D : C {};
  void (C::*g)() = &D::f;
  void (D::*h)() = &D::f;

  struct E {
    void f();
  };
  struct F : E {
    using E::f;
    void f(int);
  };
  void (F::*i)() = &F::f;
} // namespace cwg247

namespace cwg248 { // cwg248: sup P1949
  int \u040d\u040e = 0;
} // namespace cwg248

namespace cwg249 { // cwg249: 2.7
  template<typename T> struct X { void f(); };
  template<typename T> void X<T>::f() {}
} // namespace cwg249

namespace cwg250 { // cwg250: 2.7
  typedef void (*FPtr)(double x[]);

  template<int I> void f(double x[]);
  FPtr fp = &f<3>;

  template<int I = 3> void g(double x[]);
  // cxx98-error@-1 {{default template arguments for a function template are a C++11 extension}}
  FPtr gp = &g<>;
} // namespace cwg250

namespace cwg252 { // cwg252: 3.1
  struct A {
    void operator delete(void*); // #cwg252-A
  };
  struct B {
    void operator delete(void*); // #cwg252-B
  };
  struct C : A, B {
    virtual ~C();
  };
  C::~C() {}
  // expected-error@-1 {{member 'operator delete' found in multiple base classes of different types}}
  //   expected-note@#cwg252-A {{member found by ambiguous name lookup}}
  //   expected-note@#cwg252-B {{member found by ambiguous name lookup}}

  struct D {
    void operator delete(void*, int); // #cwg252-D
    virtual ~D();
  };
  D::~D() {}
  // expected-error@-1 {{no suitable member 'operator delete' in 'D'}}
  //   expected-note@#cwg252-D {{member 'operator delete' declared here}}

  struct E {
    void operator delete(void*, int);
    void operator delete(void*) = delete; // #cwg252-E
    // cxx98-error@-1 {{deleted function definitions are a C++11 extension}}
    virtual ~E();
  };
  E::~E() {}
  // expected-error@-1 {{attempt to use a deleted function}}
  //   expected-note@#cwg252-E {{'operator delete' has been explicitly marked deleted here}}

  struct F {
    // If both functions are available, the first one is a placement delete.
    void operator delete(void*, size_t);
    void operator delete(void*) = delete; // #cwg252-F
    // cxx98-error@-1 {{deleted function definitions are a C++11 extension}}
    virtual ~F();
  };
  F::~F() {}
  // expected-error@-1 {{attempt to use a deleted function}}
  //   expected-note@#cwg252-F {{'operator delete' has been explicitly marked deleted here}}

  struct G {
    void operator delete(void*, size_t);
    virtual ~G();
  };
  G::~G() {}
} // namespace cwg252

namespace cwg254 { // cwg254: 2.9
  template<typename T> struct A {
    typedef typename T::type type; // ok even if this is a typedef-name, because
                                   // it's not an elaborated-type-specifier
    typedef struct T::type foo;
    // expected-error@-1 {{typedef 'type' cannot be referenced with the 'struct' specifier}}
    //   expected-note@#cwg254-instantiation {{in instantiation of template class 'cwg254::A<cwg254::C>' requested here}}
    //   expected-note@#cwg254-C {{declared here}}
  };
  struct B { struct type {}; };
  struct C { typedef struct {} type; }; // #cwg254-C
  A<B>::type n;
  A<C>::type n; // #cwg254-instantiation
} // namespace cwg254

namespace cwg255 { // cwg255: 2.7
struct S {
  void operator delete(void *){}
  void operator delete(void *, int){}
};
void f(S *p) { delete p; }
} // namespace cwg255

// cwg256: dup 624

namespace cwg257 { // cwg257: 3.4
  struct A { A(int); }; // #cwg257-A
  struct B : virtual A {
    B() {}
    virtual void f() = 0;
  };
  struct C : B {
    C() {}
  };
  struct D : B {
    D() {}
    // expected-error@-1 {{constructor for 'cwg257::D' must explicitly initialize the base class 'A' which does not have a default constructor}}
    //   expected-note@#cwg257-A {{'cwg257::A' declared here}}
    void f();
  };
} // namespace cwg257

namespace cwg258 { // cwg258: 2.8
  struct A {
    void f(const int);
    template<typename> void g(int);
    float &h() const;
  };
  struct B : A {
    using A::f;
    using A::g;
    using A::h;
    int &f(int);
    template<int> int &g(int); // #cwg258-B-g
    int &h();
  } b;
  int &w = b.f(0);
  int &x = b.g<int>(0);
  // expected-error@-1 {{no matching member function for call to 'g'}}
  //   expected-note@#cwg258-B-g {{candidate template ignored: invalid explicitly-specified argument for 1st template parameter}}
  int &y = b.h();
  float &z = const_cast<const B&>(b).h();

  struct C {
    virtual void f(const int) = 0;
  };
  struct D : C {
    void f(int);
  } d;

  struct E {
    virtual void f() = 0; // #cwg258-E-f
  };
  struct F : E {
    void f() const {}
  } f;
  // expected-error@-1 {{variable type 'struct F' is an abstract class}}
  //   expected-note@#cwg258-E-f {{unimplemented pure virtual method 'f' in 'F'}}
} // namespace cwg258

namespace cwg259 { // cwg259: 4
  template<typename T> struct A {};
  template struct A<int>; // #cwg259-A-int
  template struct A<int>;
  // expected-error@-1 {{duplicate explicit instantiation of 'A<int>'}}
  //   expected-note@#cwg259-A-int {{previous explicit instantiation is here}}

  template<> struct A<float>; // #cwg259-A-float
  template struct A<float>;
  // expected-warning@-1 {{explicit instantiation of 'A<float>' that occurs after an explicit specialization has no effect}}
  //   expected-note@#cwg259-A-float {{previous template specialization is here}}

  template struct A<char>; // #cwg259-A-char
  template<> struct A<char>;
  // expected-error@-1 {{explicit specialization of 'cwg259::A<char>' after instantiation}}
  //   expected-note@#cwg259-A-char {{explicit instantiation first required here}}

  template<> struct A<double>;
  template<> struct A<double>;
  template<> struct A<double> {}; // #cwg259-A-double
  template<> struct A<double> {};
  // expected-error@-1 {{redefinition of 'A<double>'}}
  //   expected-note@#cwg259-A-double {{previous definition is here}}

  template<typename T> struct B; // #cwg259-B
  template struct B<int>;
  // expected-error@-1 {{explicit instantiation of undefined template 'cwg259::B<int>'}}
  //   expected-note@#cwg259-B {{template is declared here}}

  template<> struct B<float>; // #cwg259-B-float
  template struct B<float>;
  // expected-warning@-1 {{explicit instantiation of 'B<float>' that occurs after an explicit specialization has no effect}}
  //   expected-note@#cwg259-B-float {{previous template specialization is here}}
} // namespace cwg259

// FIXME: When cwg260 is resolved, also add tests for CWG507.

namespace cwg261 { // cwg261: no
#pragma clang diagnostic push
#pragma clang diagnostic warning "-Wused-but-marked-unused"

  // FIXME: This is ill-formed, with a diagnostic required, because operator new
  // and operator delete are inline and odr-used, but not defined in this
  // translation unit.
  // We're also missing the -Wused-but-marked-unused diagnostic here.
  struct A {
    inline void *operator new(size_t) __attribute__((unused));
    inline void operator delete(void*) __attribute__((unused));
    A() {}
  };

  // FIXME: This is ill-formed, with a required diagnostic, for the same
  // reason.
  struct B {
    inline void operator delete(void*) __attribute__((unused));
    ~B() {}
  };
  struct C {
    inline void operator delete(void*) __attribute__((unused));
    virtual ~C() {}
    // expected-warning@-1 {{'operator delete' was marked unused but was used}}
  };

  struct D {
    inline void operator delete(void*) __attribute__((unused));
  };
  void h() { C::operator delete(0); }
  // expected-warning@-1 {{'operator delete' was marked unused but was used}}

#pragma clang diagnostic pop
} // namespace cwg261

namespace cwg262 { // cwg262: 2.7
  int f(int = 0, ...);
  int k = f();
  int l = f(0);
  int m = f(0, 0);
} // namespace cwg262

namespace cwg263 { // cwg263: 3.3
  struct X {};
  struct Y {
#if __cplusplus < 201103L
    friend X::X() throw();
    friend X::~X() throw();
#elif __cplusplus <= 201703L
    friend constexpr X::X() noexcept;
    friend X::~X();
#else
    friend constexpr X::X() noexcept;
    friend constexpr X::~X();
#endif
    Y::Y();
    // expected-error@-1 {{extra qualification on member 'Y'}}
    Y::~Y();
    // expected-error@-1 {{extra qualification on member '~Y'}}
  };
} // namespace cwg263

// cwg265: dup 353
// cwg266: na
// cwg269: na
// cwg270: na

namespace cwg272 { // cwg272: 2.7
  struct X {
    void f() {
      this->~X();
      X::~X();
      ~X();
      // expected-error@-1 {{invalid argument type 'X' to unary expression}}
    }
  };
} // namespace cwg272

// cwg273 is in cwg273.cpp
// cwg274: na

namespace cwg275 { // cwg275: no
  namespace N {
    template <class T> void f(T) {} // #cwg275-N-f
    template <class T> void g(T) {} // #cwg275-N-g
    template <> void f(int);
    template <> void f(char);
    template <> void f(double);
    template <> void g(char);
  }

  using namespace N;

  namespace M {
    template <> void N::f(char) {}
    // expected-error@-1 {{cannot define or redeclare 'f' here because namespace 'M' does not enclose namespace 'N'}}
    template <class T> void g(T) {}
    template <> void g(char) {}
    // FIXME: this should be rejected in c++98 too
    template void f(long);
    // since-cxx11-error@-1 {{explicit instantiation of 'cwg275::N::f' must occur in namespace 'N'}}
    //   since-cxx11-note@#cwg275-N-f {{explicit instantiation refers here}}
    // FIXME: this should be rejected in c++98 too
    template void N::f(unsigned long);
    // since-cxx11-error@-1 {{explicit instantiation of 'f' not in a namespace enclosing 'N'}}
    //   since-cxx11-note@#cwg275-N-f {{explicit instantiation refers here}}
    template void h(long);
    // expected-error@-1 {{explicit instantiation of 'h' does not refer to a function template, variable template, member function, member class, or static data member}}
    template <> void f(double) {}
    // expected-error@-1 {{no function template matches function template specialization 'f'}}
  }

  template <class T> void g(T) {} // #cwg275-g

  template <> void N::f(char) {}
  template <> void f(int) {}
  // expected-error@-1 {{no function template matches function template specialization 'f'}}

  // FIXME: this should be rejected in c++98 too
  template void f(short);
  // since-cxx11-error@-1 {{explicit instantiation of 'cwg275::N::f' must occur in namespace 'N'}}
  //   since-cxx11-note@#cwg275-N-f {{explicit instantiation refers here}}
  template void N::f(unsigned short);

  // FIXME: this should probably be valid. the wording from the issue
  // doesn't clarify this, but it follows from the usual rules.
  template void g(int);
  // expected-error@-1 {{partial ordering for explicit instantiation of 'g' is ambiguous}}
  //   expected-note@#cwg275-g {{explicit instantiation candidate function 'cwg275::g<int>' template here [with T = int]}}
  //   expected-note@#cwg275-N-g {{explicit instantiation candidate function 'cwg275::N::g<int>' template here [with T = int]}}

  // FIXME: likewise, this should also be valid.
  template<typename T> void f(T) {} // #cwg275-f
  template void f(short);
  // expected-error@-1 {{partial ordering for explicit instantiation of 'f' is ambiguous}}
  //   expected-note@#cwg275-f {{explicit instantiation candidate function 'cwg275::f<short>' template here [with T = short]}}
  //   expected-note@#cwg275-N-f {{explicit instantiation candidate function 'cwg275::N::f<short>' template here [with T = short]}}
} // namespace cwg275

// cwg276: na

namespace cwg277 { // cwg277: 3.1
  typedef int *intp;
  int *p = intp();
  static_assert(__enable_constant_folding(!intp()), "");
} // namespace cwg277

// cwg279 is in cwg279.cpp

namespace cwg280 { // cwg280: 2.9
  typedef void f0();
  typedef void f1(int);
  typedef void f2(int, int);
  typedef void f3(int, int, int);
  struct A {
    operator f1*(); // #cwg280-A-f1
    operator f2*();
  };
  struct B {
    operator f0*(); // #cwg280-B-f0
  private:
    operator f3*(); // #cwg280-B-f3
  };
  struct C {
    operator f0*(); // #cwg280-C-f0
    operator f1*(); // #cwg280-C-f1
    operator f2*(); // #cwg280-C-f2
    operator f3*(); // #cwg280-C-f3
  };
  struct D : private A, B { // #cwg280-D
    operator f2*(); // #cwg280-D-f2
  } d;
  struct E : C, D {} e;
  void g() {
    d(); // ok, public
    d(0);
    // expected-error@-1 {{'operator void (*)(int)' is a private member of 'cwg280::A'}}
    //   expected-note@#cwg280-D {{constrained by private inheritance here}}
    //   expected-note@#cwg280-A-f1 {{member is declared here}}
    d(0, 0); // ok, suppressed by member in D
    d(0, 0, 0);
    // expected-error@-1 {{'operator void (*)(int, int, int)' is a private member of 'cwg280::B'}}
    //   expected-note@#cwg280-B-f3 {{declared private here}}
    e();
    // expected-error@-1 {{call to object of type 'struct E' is ambiguous}}
    //   expected-note@#cwg280-B-f0 {{conversion candidate of type 'void (*)()'}}
    //   expected-note@#cwg280-C-f0 {{conversion candidate of type 'void (*)()'}}
    e(0);
    // expected-error@-1 {{call to object of type 'struct E' is ambiguous}}
    //   expected-note@#cwg280-A-f1 {{conversion candidate of type 'void (*)(int)'}}
    //   expected-note@#cwg280-C-f1 {{conversion candidate of type 'void (*)(int)'}}
    e(0, 0);
    // expected-error@-1 {{call to object of type 'struct E' is ambiguous}}
    //   expected-note@#cwg280-C-f2 {{conversion candidate of type 'void (*)(int, int)'}}
    //   expected-note@#cwg280-D-f2 {{conversion candidate of type 'void (*)(int, int)'}}
    e(0, 0, 0);
    // expected-error@-1 {{call to object of type 'struct E' is ambiguous}}
    //   expected-note@#cwg280-B-f3 {{conversion candidate of type 'void (*)(int, int, int)'}}
    //   expected-note@#cwg280-C-f3 {{conversion candidate of type 'void (*)(int, int, int)'}}
  }
} // namespace cwg280

namespace cwg281 { // cwg281: no
  void a();
  inline void b();

  void d();
  inline void e();

  struct S {
    friend inline void a(); // FIXME: ill-formed
    friend inline void b();
    friend inline void c(); // FIXME: ill-formed
    friend inline void d() {}
    friend inline void e() {}
    friend inline void f() {}
  };
} // namespace cwg281

namespace cwg283 { // cwg283: 2.7
  template<typename T> // #cwg283-template
  struct S {
    friend class T;
    // expected-error@-1 {{declaration of 'T' shadows template parameter}}
    //   expected-note@#cwg283-template {{template parameter is declared here}}
    class T;
    // expected-error@-1 {{declaration of 'T' shadows template parameter}}
    //   expected-note@#cwg283-template {{template parameter is declared here}}
  };
} // namespace cwg283

namespace cwg284 { // cwg284: no
  namespace A {
    struct X;
    enum Y {};
    class Z {};
  }
  namespace B {
    struct W;
    using A::X;
    using A::Y;
    using A::Z;
  }
  struct B::V {};
  // expected-error@-1 {{no struct named 'V' in namespace 'cwg284::B'}}
  struct B::W {};
  struct B::X {}; // FIXME: ill-formed
  enum B::Y e; // ok per cwg417
  class B::Z z; // ok per cwg417

  struct C {
    struct X;
    enum Y {};
    class Z {};
  };
  struct D : C {
    struct W;
    using C::X;
    using C::Y;
    using C::Z;
  };
  struct D::V {};
  // expected-error@-1 {{no struct named 'V' in 'cwg284::D'}}
  struct D::W {};
  struct D::X {}; // FIXME: ill-formed
  enum D::Y e2; // ok per cwg417
  class D::Z z2; // ok per cwg417
} // namespace cwg284

namespace cwg285 { // cwg285: 2.7
  template<typename T> void f(T, int); // #cwg285-f-T-int
  template<typename T> void f(int, T); // #cwg285-f-int-T
  template<> void f<int>(int, int) {}
  // expected-error@-1 {{function template specialization 'f' ambiguously refers to more than one function template; explicitly specify additional template arguments to identify a particular function template}}
  //   expected-note@#cwg285-f-int-T {{function template 'cwg285::f<int>' matches specialization [with T = int]}}
  //   expected-note@#cwg285-f-T-int {{function template 'cwg285::f<int>' matches specialization [with T = int]}}
} // namespace cwg285

namespace cwg286 { // cwg286: 2.8
  template<class T> struct A {
    class C {
      template<class T2> struct B {}; // #cwg286-B
    };
  };

  template<class T>
  template<class T2>
  struct A<T>::C::B<T2*> { };

  A<short>::C::B<int*> absip;
  // expected-error@-1 {{'B' is a private member of 'cwg286::A<short>::C'}}
  //   expected-note@#cwg286-B {{implicitly declared private here}}
} // namespace cwg286

// cwg288: na

namespace cwg289 { // cwg289: 2.7
  struct A; // #cwg289-A
  struct B : A {};
  // expected-error@-1 {{base class has incomplete type}}
  //   expected-note@#cwg289-A {{forward declaration of 'cwg289::A'}}

  template<typename T> struct C { typename T::error error; };
  // expected-error@-1 {{type 'int' cannot be used prior to '::' because it has no members}}
  //   expected-note@#cwg289-C-int {{in instantiation of template class 'cwg289::C<int>' requested here}}
  struct D : C<int> {}; // #cwg289-C-int
} // namespace cwg289

// cwg290: na
// cwg291: dup 391
// cwg292 is in cwg292.cpp

namespace cwg294 { // cwg294: no
  void f() throw(int);
  // since-cxx17-error@-1 {{ISO C++17 does not allow dynamic exception specifications}}
  //   since-cxx17-note@-2 {{use 'noexcept(false)' instead}}
  int main() {
    (void)static_cast<void (*)() throw()>(f); // FIXME: ill-formed in C++14 and before
    // FIXME: since-cxx17-error@-1 {{static_cast from 'void (*)() throw(int)' to 'void (*)() throw()' is not allowed}}
    //
    // Irony: the above is valid in C++17 and beyond, but that's exactly when
    // we reject it. In C++14 and before, this is ill-formed because an
    // exception-specification is not permitted in a type-id. In C++17, this is
    // valid because it's the inverse of a standard conversion sequence
    // containing a function pointer conversion. (Well, it's actually not valid
    // yet, as a static_cast is not permitted to reverse a function pointer
    // conversion, but that is being changed by core issue).
    (void)static_cast<void (*)() throw(int)>(f); // FIXME: ill-formed in C++14 and before
    // since-cxx17-error@-1 {{ISO C++17 does not allow dynamic exception specifications}}
    //   since-cxx17-note@-2 {{use 'noexcept(false)' instead}}

    void (*p)() throw() = f;
    // cxx98-14-error@-1 {{target exception specification is not superset of source}}
    // since-cxx17-error@-2 {{cannot initialize a variable of type 'void (*)() throw()' with an lvalue of type 'void () throw(int)': different exception specifications}}
    void (*q)() throw(int) = f;
    // since-cxx17-error@-1 {{ISO C++17 does not allow dynamic exception specifications}}
    //   since-cxx17-note@-2 {{use 'noexcept(false)' instead}}
  }
} // namespace cwg294

namespace cwg295 { // cwg295: 3.7
  typedef int f();
  const f g;
  // expected-warning@-1 {{'const' qualifier on function type 'f' (aka 'int ()') has no effect}}
  f &r = g;
  template<typename T> struct X {
    const T &f;
  };
  X<f> x = {g};

  typedef int U();
  typedef const U U;
  // expected-warning@-1 {{'const' qualifier on function type 'U' (aka 'int ()') has no effect}}

  typedef int (*V)();
  typedef volatile U *V;
  // expected-warning@-1 {{'volatile' qualifier on function type 'U' (aka 'int ()') has no effect}}
} // namespace cwg295

namespace cwg296 { // cwg296: 2.7
  struct A {
    static operator int() { return 0; }
    // expected-error@-1 {{conversion function must be a non-static member function}}
  };
} // namespace cwg296

namespace cwg298 { // cwg298: 3.1
  struct A {
    typedef int type;
    A();
    ~A();
  };
  typedef A B; // #cwg298-B
  typedef const A C; // #cwg298-C

  A::type i1;
  B::type i2;
  C::type i3;

  struct A a;
  struct B b;
  // expected-error@-1 {{typedef 'B' cannot be referenced with the 'struct' specifier}}
  //   expected-note@#cwg298-B {{declared here}}
  struct C c;
  // expected-error@-1 {{typedef 'C' cannot be referenced with the 'struct' specifier}}
  //   expected-note@#cwg298-C {{declared here}}

  B::B() {}
  // expected-error@-1 {{a type specifier is required for all declarations}}
  B::A() {} // ok
  C::~C() {}
  // expected-error@-1 {{destructor cannot be declared using a typedef 'C' (aka 'const cwg298::A') of the class name}}

  typedef struct D E; // #cwg298-E
  struct E {};
  // expected-error@-1 {{definition of type 'E' conflicts with typedef of the same name}}
  //   expected-note@#cwg298-E {{'E' declared here}}

  struct F {
    ~F();
  };
  typedef const F G;
  G::~F() {} // ok
} // namespace cwg298

namespace cwg299 { // cwg299: 2.8 c++11
  struct S {
    operator int();
  };
  struct T {
    operator int(); // #cwg299-int
    operator unsigned short(); // #cwg299-ushort
  };
  // FIXME: should this apply to c++98 mode?
  int *p = new int[S()];
  // cxx98-error@-1 {{implicit conversion from array size expression of type 'S' to integral type 'int' is a C++11 extension}}
  int *q = new int[T()]; // #cwg299-q
  // cxx98-11-error@#cwg299-q {{ambiguous conversion of array size expression of type 'T' to an integral or enumeration type}}
  //  cxx98-11-note@#cwg299-int {{conversion to integral type 'int' declared here}}
  //  cxx98-11-note@#cwg299-ushort {{conversion to integral type 'unsigned short' declared here}}
  // since-cxx14-error-re@#cwg299-q {{{{conversion from 'T' to 'unsigned (long long|long|int)' is ambiguous}}}}
  //  since-cxx14-note@#cwg299-int {{candidate function}}
  //  since-cxx14-note@#cwg299-ushort {{candidate function}}
} // namespace cwg299