llvm-project/clang/test/CXX/drs/dr15xx.cpp

// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++1z -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors

#if __cplusplus < 201103L
// expected-no-diagnostics
#endif

namespace dr1550 { // dr1550: yes
  int f(bool b, int n) {
    return (b ? (throw 0) : n) + (b ? n : (throw 0));
  }
}

namespace dr1560 { // dr1560: 3.5
  void f(bool b, int n) {
    (b ? throw 0 : n) = (b ? n : throw 0) = 0;
  }
  class X { X(const X&); };
  const X &get();
  const X &x = true ? get() : throw 0;
}

namespace dr1573 { // dr1573: 3.9
#if __cplusplus >= 201103L
  // ellipsis is inherited (p0136r1 supersedes this part).
  struct A { A(); A(int, char, ...); };
  struct B : A { using A::A; };
  B b(1, 'x', 4.0, "hello"); // ok

  // inherited constructor is effectively constexpr if the user-written constructor would be
  struct C { C(); constexpr C(int) {} };
  struct D : C { using C::C; };
  constexpr D d = D(0); // ok
  struct E : C { using C::C; A a; }; // expected-note {{non-literal type}}
  constexpr E e = E(0); // expected-error {{non-literal type}}
  // FIXME: This diagnostic is pretty bad; we should explain that the problem
  // is that F::c would be initialized by a non-constexpr constructor.
  struct F : C { using C::C; C c; }; // expected-note {{here}}
  constexpr F f = F(0); // expected-error {{constant expression}} expected-note {{constructor inherited from base class 'C'}}

  // inherited constructor is effectively deleted if the user-written constructor would be
  struct G { G(int); }; // expected-note {{declared here}}
  struct H : G { using G::G; G g; }; // expected-error {{cannot use constructor inherited from base class 'G'; member 'g' of 'dr1573::H' does not have a default constructor}} expected-note {{declared here}}
  H h(0); // expected-note {{first required here}}
#endif
}

#if __cplusplus >= 201103L
namespace std {
  typedef decltype(sizeof(int)) size_t;

  // libc++'s implementation
  template <class _E>
  class initializer_list
  {
    const _E* __begin_;
    size_t    __size_;

    initializer_list(const _E* __b, size_t __s)
    : __begin_(__b), __size_(__s) {}

  public:
    typedef _E        value_type;
    typedef const _E& reference;
    typedef const _E& const_reference;
    typedef size_t    size_type;

    typedef const _E* iterator;
    typedef const _E* const_iterator;

    initializer_list() : __begin_(nullptr), __size_(0) {}

    size_t    size()  const {return __size_;}
    const _E* begin() const {return __begin_;}
    const _E* end()   const {return __begin_ + __size_;}
  };

  template < class _T1, class _T2 > struct pair { _T2 second; };

  template<typename T> struct basic_string {
    basic_string(const T* x) {}
    ~basic_string() {};
  };
  typedef basic_string<char> string;

} // std

namespace dr1589 {   // dr1589: 3.7 c++11
  // Ambiguous ranking of list-initialization sequences

  void f0(long, int=0);                 // Would makes selection of #0 ambiguous
  void f0(long);                        // #0
  void f0(std::initializer_list<int>);  // #00
  void g0() { f0({1L}); }               // chooses #00

  void f1(int, int=0);                    // Would make selection of #1 ambiguous
  void f1(int);                           // #1
  void f1(std::initializer_list<long>);   // #2
  void g1() { f1({42}); }                 // chooses #2

  void f2(std::pair<const char*, const char*>, int = 0); // Would makes selection of #3 ambiguous
  void f2(std::pair<const char*, const char*>); // #3
  void f2(std::initializer_list<std::string>);  // #4
  void g2() { f2({"foo","bar"}); }              // chooses #4

  namespace with_error {
    void f0(long);                        // #0    expected-note {{candidate function}}
    void f0(std::initializer_list<int>);  // #00   expected-note {{candidate function}}
    void f0(std::initializer_list<int>, int = 0);  // Makes selection of #00 ambiguous \
    // expected-note {{candidate function}}
    void g0() { f0({1L}); }                 // chooses #00    expected-error{{call to 'f0' is ambiguous}}

    void f1(int);                           // #1   expected-note {{candidate function}}
    void f1(std::initializer_list<long>);   // #2   expected-note {{candidate function}}
    void f1(std::initializer_list<long>, int = 0);   // Makes selection of #00 ambiguous \
    // expected-note {{candidate function}}
    void g1() { f1({42}); }                 // chooses #2   expected-error{{call to 'f1' is ambiguous}}

    void f2(std::pair<const char*, const char*>); // #3   TODO: expected- note {{candidate function}}
    void f2(std::initializer_list<std::string>);  // #4   expected-note {{candidate function}}
    void f2(std::initializer_list<std::string>, int = 0);   // Makes selection of #00 ambiguous \
    // expected-note {{candidate function}}
    void g2() { f2({"foo","bar"}); }        // chooses #4   expected-error{{call to 'f2' is ambiguous}}
  }

} // dr1589

namespace dr1591 {  //dr1591. Deducing array bound and element type from initializer list 
  template<class T, int N> int h(T const(&)[N]);
  int X = h({1,2,3});              // T deduced to int, N deduced to 3
  
  template<class T> int j(T const(&)[3]);
  int Y = j({42});                 // T deduced to int, array bound not considered

  struct Aggr { int i; int j; };
  template<int N> int k(Aggr const(&)[N]); //expected-note{{not viable}}
  int Y0 = k({1,2,3});              //expected-error{{no matching function}}
  int Z = k({{1},{2},{3}});        // OK, N deduced to 3

  template<int M, int N> int m(int const(&)[M][N]);
  int X0 = m({{1,2},{3,4}});        // M and N both deduced to 2

  template<class T, int N> int n(T const(&)[N], T);
  int X1 = n({{1},{2},{3}},Aggr()); // OK, T is Aggr, N is 3
  
  
  namespace check_multi_dim_arrays {
    template<class T, int N, int M, int O> int ***f(const T (&a)[N][M][O]); //expected-note{{deduced conflicting values}}
    template<class T, int N, int M> int **f(const T (&a)[N][M]); //expected-note{{couldn't infer}}
   
   template<class T, int N> int *f(const T (&a)[N]); //expected-note{{couldn't infer}}
    int ***p3 = f({  {  {1,2}, {3, 4}  }, {  {5,6}, {7, 8}  }, {  {9,10}, {11, 12}  } });
    int ***p33 = f({  {  {1,2}, {3, 4}  }, {  {5,6}, {7, 8}  }, {  {9,10}, {11, 12, 13}  } }); //expected-error{{no matching}}
    int **p2 = f({  {1,2,3}, {3, 4, 5}  });
    int **p22 = f({  {1,2}, {3, 4}  });
    int *p1 = f({1, 2, 3});
  }
  namespace check_multi_dim_arrays_rref {
    template<class T, int N, int M, int O> int ***f(T (&&a)[N][M][O]); //expected-note{{deduced conflicting values}}
    template<class T, int N, int M> int **f(T (&&a)[N][M]); //expected-note{{couldn't infer}}
   
    template<class T, int N> int *f(T (&&a)[N]); //expected-note{{couldn't infer}}
    int ***p3 = f({  {  {1,2}, {3, 4}  }, {  {5,6}, {7, 8}  }, {  {9,10}, {11, 12}  } });
    int ***p33 = f({  {  {1,2}, {3, 4}  }, {  {5,6}, {7, 8}  }, {  {9,10}, {11, 12, 13}  } }); //expected-error{{no matching}}
    int **p2 = f({  {1,2,3}, {3, 4, 5}  });
    int **p22 = f({  {1,2}, {3, 4}  });
    int *p1 = f({1, 2, 3});
  }
  
  namespace check_arrays_of_init_list {
    template<class T, int N> float *f(const std::initializer_list<T> (&)[N]);
    template<class T, int N> double *f(const T(&)[N]);
    double *p = f({1, 2, 3});
    float *fp = f({{1}, {1, 2}, {1, 2, 3}});
  }
  namespace core_reflector_28543 {
    
    template<class T, int N> int *f(T (&&)[N]);  // #1
    template<class T> char *f(std::initializer_list<T> &&);  //#2
    template<class T, int N, int M> int **f(T (&&)[N][M]); //#3 expected-note{{candidate}}
    template<class T, int N> char **f(std::initializer_list<T> (&&)[N]); //#4 expected-note{{candidate}}

    template<class T> short *f(T (&&)[2]);  //#5

    template<class T> using Arr = T[];
     
    char *pc = f({1, 2, 3}); // OK prefer #2 via 13.3.3.2 [over.ics.rank]
    char *pc2 = f({1, 2}); // #2 also 
    int *pi = f(Arr<int>{1, 2, 3}); // OK prefer #1

    void *pv1 = f({ {1, 2, 3}, {4, 5, 6} }); // expected-error{{ambiguous}} btw 3 & 4
    char **pcc = f({ {1}, {2, 3} }); // OK #4

    short *ps = f(Arr<int>{1, 2});  // OK #5
  }
} // dr1591

#endif