clang/test/CXX/drs/cwg27xx.cpp

// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++98 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++11 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++14 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++17 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++20 -pedantic-errors -verify=expected %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++23 -pedantic-errors -verify=expected,since-cxx23 %s
// RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++2c -pedantic-errors -verify=expected,since-cxx23,since-cxx26 %s

namespace cwg2718 { // cwg2718: 2.7
struct B {};
struct D;

void f(B b) {
  static_cast<D&>(b);
  // expected-error@-1 {{non-const lvalue reference to type 'D' cannot bind to a value of unrelated type 'B'}}
}

struct D : B {};
} // namespace cwg2718

namespace cwg2759 { // cwg2759: 19
#if __cplusplus >= 201103L

struct CStruct {
  int one;
  int two;
};

struct CEmptyStruct {};
struct CEmptyStruct2 {};

struct CStructNoUniqueAddress {
  int one;
  [[no_unique_address]] int two;
};

struct CStructNoUniqueAddress2 {
  int one;
  [[no_unique_address]] int two;
};

union UnionLayout {
  int a;
  double b;
  CStruct c;
  [[no_unique_address]] CEmptyStruct d;
  [[no_unique_address]] CEmptyStruct2 e;
};

union UnionLayout2 {
  CStruct c;
  int a;
  CEmptyStruct2 e;
  double b;
  [[no_unique_address]] CEmptyStruct d;
};

union UnionLayout3 {
  CStruct c;
  int a;
  double b;
  [[no_unique_address]] CEmptyStruct d;
};

struct StructWithAnonUnion {
  union {
    int a;
    double b;
    CStruct c;
    [[no_unique_address]] CEmptyStruct d;
    [[no_unique_address]] CEmptyStruct2 e;
  };
};

struct StructWithAnonUnion2 {
  union {
    CStruct c;
    int a;
    CEmptyStruct2 e;
    double b;
    [[no_unique_address]] CEmptyStruct d;
  };
};

struct StructWithAnonUnion3 {
  union {
    CStruct c;
    int a;
    CEmptyStruct2 e;
    double b;
    [[no_unique_address]] CEmptyStruct d;
  } u;
};

static_assert(__is_layout_compatible(CStruct, CStructNoUniqueAddress) != bool(__has_cpp_attribute(no_unique_address)), "");
static_assert(__is_layout_compatible(CStructNoUniqueAddress, CStructNoUniqueAddress2) != bool(__has_cpp_attribute(no_unique_address)), "");
static_assert(!__is_layout_compatible(UnionLayout, UnionLayout2), "");
static_assert(!__is_layout_compatible(UnionLayout, UnionLayout3), "");
static_assert(!__is_layout_compatible(StructWithAnonUnion, StructWithAnonUnion2), "");
static_assert(!__is_layout_compatible(StructWithAnonUnion, StructWithAnonUnion3), "");
#endif
} // namespace cwg2759

namespace cwg2789 { // cwg2789: 18
#if __cplusplus >= 202302L
template <typename T = int>
struct Base {
    constexpr void g(); // #cwg2789-g1
};

template <typename T = int>
struct Base2 {
    constexpr void g() requires true;  // #cwg2789-g2
};

template <typename T = int>
struct S : Base<T>, Base2<T> {
    constexpr void f();
    constexpr void f(this S&) requires true{};

    using Base<T>::g;
    using Base2<T>::g;
};

void test() {
    S<> s;
    s.f();
    s.g();
    // since-cxx23-error@-1 {{call to member function 'g' is ambiguous}}
    //   since-cxx23-note@#cwg2789-g1 {{candidate function}}
    //   since-cxx23-note@#cwg2789-g2 {{candidate function}}
}
#endif
}

namespace cwg2798 { // cwg2798: 17
#if __cpp_static_assert >= 202306
struct string {
  constexpr string() {
    data_ = new char[6]();
    __builtin_memcpy(data_, "Hello", 5);
    data_[5] = 0;
  }
  constexpr ~string() { delete[] data_; }
  constexpr unsigned long size() const { return 5; };
  constexpr const char *data() const { return data_; }

  char *data_;
};
struct X {
  string s;
};
consteval X f() { return {}; }

static_assert(false, f().s);
// since-cxx26-error@-1 {{static assertion failed: Hello}}
#endif
} // namespace cwg2798