//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17

// <span>

// template<class OtherElementType, size_t OtherExtent>
//    constexpr span(const span<OtherElementType, OtherExtent>& s) noexcept;
//
//  Remarks: This constructor shall not participate in overload resolution unless:
//      Extent == dynamic_extent || Extent == OtherExtent is true, and
//      OtherElementType(*)[] is convertible to ElementType(*)[].

#include <span>
#include <cassert>
#include <string>

#include "test_macros.h"

template <class T, std::size_t extent, size_t otherExtent>
std::span<T, extent> createImplicitSpan(std::span<T, otherExtent> s) {
  return {s}; // expected-error {{chosen constructor is explicit in copy-initialization}}
}

void checkCV() {
  //  std::span<               int>   sp;
  std::span<const int> csp;
  std::span< volatile int> vsp;
  std::span<const volatile int> cvsp;

  //  std::span<               int, 0>   sp0;
  std::span<const int, 0> csp0;
  std::span< volatile int, 0> vsp0;
  std::span<const volatile int, 0> cvsp0;

  //  Try to remove const and/or volatile (dynamic -> dynamic)
  {
    std::span< int> s1{csp};  // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
    std::span< int> s2{vsp};  // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
    std::span< int> s3{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}

    std::span<const int> s4{vsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int>'}}
    std::span<const int> s5{cvsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int>'}}

    std::span< volatile int> s6{csp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int>'}}
    std::span< volatile int> s7{cvsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int>'}}
  }

  //  Try to remove const and/or volatile (static -> static)
  {
    std::span< int, 0> s1{csp0}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
    std::span< int, 0> s2{vsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
    std::span< int, 0> s3{cvsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<int, 0>'}}

    std::span<const int, 0> s4{vsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int, 0>'}}
    std::span<const int, 0> s5{cvsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int, 0>'}}

    std::span< volatile int, 0> s6{csp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
    std::span< volatile int, 0> s7{cvsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
  }

  //  Try to remove const and/or volatile (static -> dynamic)
  {
    std::span< int> s1{csp0};  // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
    std::span< int> s2{vsp0};  // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
    std::span< int> s3{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}

    std::span<const int> s4{vsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int>'}}
    std::span<const int> s5{cvsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int>'}}

    std::span< volatile int> s6{csp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int>'}}
    std::span< volatile int> s7{cvsp0};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int>'}}
  }

  //  Try to remove const and/or volatile (static -> static)
  {
    std::span< int, 0> s1{csp};  // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
    std::span< int, 0> s2{vsp};  // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
    std::span< int, 0> s3{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}

    std::span<const int, 0> s4{vsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int, 0>'}}
    std::span<const int, 0> s5{cvsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<const int, 0>'}}

    std::span< volatile int, 0> s6{csp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
    std::span< volatile int, 0> s7{cvsp};
    // expected-error@-1 {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
  }
}

int main(int, char**) {
  std::span<int> sp;
  std::span<int, 0> sp0;

  std::span<float> s1{sp};     // expected-error {{no matching constructor for initialization of 'std::span<float>'}}
  std::span<float> s2{sp0};    // expected-error {{no matching constructor for initialization of 'std::span<float>'}}
  std::span<float, 0> s3{sp};  // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}
  std::span<float, 0> s4{sp0}; // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}

  checkCV();

  // explicit constructor necessary
  {
    createImplicitSpan<int, 1>(sp);
  }

  return 0;
}