clang/test/CXX/drs/cwg22xx.cpp

// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors


namespace cwg2211 { // cwg2211: 8
#if __cplusplus >= 201103L
void f() {
  int a;
  auto f = [a](int a) { (void)a; };
  // since-cxx11-error@-1 {{a lambda parameter cannot shadow an explicitly captured entity}}
  //   since-cxx11-note@-2 {{variable 'a' is explicitly captured here}}
  auto g = [=](int a) { (void)a; };
}
#endif
} // namespace cwg2211

namespace cwg2213 { // cwg2213: 2.7
template <typename T, typename U>
struct A;

template <typename U>
struct A<int, U>;
} // namespace cwg2213

namespace cwg2229 { // cwg2229: 7
struct AnonBitfieldQualifiers {
  const unsigned : 1;
  // expected-error@-1 {{anonymous bit-field cannot have qualifiers}}
  volatile unsigned : 1;
  // expected-error@-1 {{anonymous bit-field cannot have qualifiers}}
  const volatile unsigned : 1;
  // expected-error@-1 {{anonymous bit-field cannot have qualifiers}}

  unsigned : 1;
  const unsigned i1 : 1;
  volatile unsigned i2 : 1;
  const volatile unsigned i3 : 1;
};
} // namespace cwg2229

namespace cwg2233 { // cwg2233: 11
#if __cplusplus >= 201103L
template <typename... T>
void f(int i = 0, T... args) {}

template <typename... T>
void g(int i = 0, T... args, T... args2) {}

template <typename... T>
void h(int i = 0, T... args, int j = 1) {}

template <typename... T, typename... U>
void i(int i = 0, T... args, int j = 1, U... args2) {}

template <class... Ts>
void j(int i = 0, Ts... ts) {}

template <>
void j<int>(int i, int j) {}

template
void j(int, int, int);

extern template
void j(int, int, int, int);

// PR23029
// Ensure instantiating the templates works.
void use() {
  f();
  f(0, 1);
  f<int>(1, 2);
  g<int>(1, 2, 3);
  h(0, 1);
  i();
  i(3);
  i<int>(3, 2);
  i<int>(3, 2, 1);
  i<int, int>(1, 2, 3, 4, 5);
  j();
  j(1);
  j(1, 2);
  j<int>(1, 2);
}

namespace MultilevelSpecialization {
  template<typename ...T> struct A {
    template <T... V> void f(int i = 0, int (&... arr)[V]);
  };
  template<> template<>
    void A<int, int>::f<1, 1>(int i, int (&arr1a)[1], int (&arr2a)[1]) {}

  // FIXME: I believe this example is valid, at least up to the first explicit
  // specialization, but Clang can't cope with explicit specializations that
  // expand packs into a sequence of parameters. If we ever start accepting
  // that, we'll need to decide whether it's OK for arr1a to be missing its
  // default argument -- how far back do we look when determining whether a
  // parameter was expanded from a pack?
  //   -- zygoloid 2020-06-02
  template<typename ...T> struct B { // #cwg2233-B
    template <T... V> void f(int i = 0, int (&... arr)[V]);
  };
  template<> template<int a, int b>
    void B<int, int>::f(int i, int (&arr1)[a], int (&arr2)[b]) {}
    // since-cxx11-error@-1 {{out-of-line definition of 'f' does not match any declaration in 'cwg2233::MultilevelSpecialization::B<int, int>'}}
    //   since-cxx11-note@#cwg2233-B {{defined here}}
  template<> template<>
    void B<int, int>::f<1, 1>(int i, int (&arr1a)[1], int (&arr2a)[1]) {}
}

namespace CheckAfterMerging1 {
  template <typename... T> void f() {
    void g(int, int = 0);
    void g(int = 0, T...);
    g();
  }
  void h() { f<int>(); }
}

namespace CheckAfterMerging2 {
  template <typename... T> void f() {
    void g(int = 0, T...);
    void g(int, int = 0);
    g();
  }
  void h() { f<int>(); }
}
#endif
} // namespace cwg2233

namespace cwg2267 { // cwg2267: no
#if __cplusplus >= 201103L
struct A {} a;
struct B { explicit B(const A&); }; // #cwg2267-struct-B

struct D { D(); };
struct C { explicit operator D(); } c;

B b1(a);
const B &b2{a}; // FIXME ill-formed
const B &b3(a);
// since-cxx11-error@-1 {{no viable conversion from 'struct A' to 'const B'}}
//   since-cxx11-note@#cwg2267-struct-B {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'struct A' to 'const B &' for 1st argument}}
//   since-cxx11-note@#cwg2267-struct-B {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'struct A' to 'B &&' for 1st argument}}
//   since-cxx11-note@#cwg2267-struct-B {{explicit constructor is not a candidate}}

D d1(c);
const D &d2{c}; // FIXME ill-formed
const D &d3(c); // FIXME ill-formed
#endif
} // namespace cwg2267

namespace cwg2273 { // cwg2273: 3.3
#if __cplusplus >= 201103L
struct A {
  A(int = 0) = delete; // #cwg2273-A
};

struct B : A { // #cwg2273-B
  using A::A;
};

B b;
// since-cxx11-error@-1 {{call to implicitly-deleted default constructor of 'B'}}
//   since-cxx11-note@#cwg2273-B {{default constructor of 'B' is implicitly deleted because base class 'A' has a deleted default constructor}}
//   since-cxx11-note@#cwg2273-A {{'A' has been explicitly marked deleted here}}
#endif
} // namespace cwg2273

namespace cwg2277 { // cwg2277: partial
#if __cplusplus >= 201103L
struct A {
  A(int, int = 0);
  void f(int, int = 0); // #cwg2277-A-f
};
struct B : A {
  B(int);
  using A::A;

  void f(int); // #cwg2277-B-f
  using A::f;
};

void g() {
  B b{0};
  b.f(0); // FIXME: this is well-formed for the same reason as initialization of 'b' above
  // since-cxx11-error@-1 {{call to member function 'f' is ambiguous}}
  //   since-cxx11-note@#cwg2277-A-f {{candidate function}}
  //   since-cxx11-note@#cwg2277-B-f {{candidate function}}
}
#endif
} // namespace cwg2277

namespace cwg2285 { // cwg2285: 4
// Note: Clang 4 implements this DR but it set a wrong value of `__cplusplus`
#if __cplusplus >= 201703L
  void test() {
    using T = int[1];
    auto [a] = T{a};
    // since-cxx17-error@-1 {{binding 'a' cannot appear in the initializer of its own decomposition declaration}}
  }
#endif
} // namespace cwg2285

namespace cwg2292 { // cwg2292: 9
#if __cplusplus >= 201103L
  template<typename T> using id = T;
  void test(int *p) {
    p->template id<int>::~id<int>();
  }
#endif
} // namespace cwg2292