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// -*- C++ -*-
//===------------------------------ span ---------------------------------===//
//
// 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++98, c++03, c++11, c++14, c++17
// <span>
// template<class Container>
// constexpr span(Container& cont);
// template<class Container>
// constexpr span(const Container& cont);
//
// Remarks: These constructors shall not participate in overload resolution unless:
// — Container is not a specialization of span,
// — Container is not a specialization of array,
// — is_array_v<Container> is false,
// — data(cont) and size(cont) are both well-formed, and
// — remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[].
//
#include <span>
#include <cassert>
#include <deque>
#include <forward_list>
#include <list>
#include <vector>
#include "test_macros.h"
// Look ma - I'm a container!
template <typename T>
struct IsAContainer {
constexpr IsAContainer() : v_{} {}
constexpr size_t size() const {return 1;}
constexpr T *data() {return &v_;}
constexpr const T *data() const {return &v_;}
constexpr const T *getV() const {return &v_;} // for checking
T v_;
};
template <typename T>
struct NotAContainerNoData {
size_t size() const {return 0;}
};
template <typename T>
struct NotAContainerNoSize {
const T *data() const {return nullptr;}
};
template <typename T>
struct NotAContainerPrivate {
private:
size_t size() const {return 0;}
const T *data() const {return nullptr;}
};
int main ()
{
// Making non-const spans from const sources (a temporary binds to `const &`)
{
std::span<int> s1{IsAContainer<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
std::span<int, 0> s2{IsAContainer<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
std::span<int> s3{std::vector<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
std::span<int, 0> s4{std::vector<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
}
// Missing size and/or data
{
std::span<const int> s1{NotAContainerNoData<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s2{NotAContainerNoData<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
std::span<const int> s3{NotAContainerNoSize<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s4{NotAContainerNoSize<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
std::span<const int> s5{NotAContainerPrivate<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s6{NotAContainerPrivate<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
// Again with the standard containers
std::span<const int> s11{std::deque<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s12{std::deque<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
std::span<const int> s13{std::list<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s14{std::list<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
std::span<const int> s15{std::forward_list<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int, 0> s16{std::forward_list<int>()}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
}
// Not the same type
{
IsAContainer<int> c;
std::span<float> s1{c}; // expected-error {{no matching constructor for initialization of 'std::span<float>'}}
std::span<float, 0> s2{c}; // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}
}
// CV wrong (dynamically sized)
{
IsAContainer<const int> c;
IsAContainer<const volatile int> cv;
IsAContainer< volatile int> v;
std::span< int> s1{c}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
std::span< int> s2{v}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
std::span< int> s3{cv}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
std::span<const int> s4{v}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span<const int> s5{cv}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
std::span< volatile int> s6{c}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
std::span< volatile int> s7{cv}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
}
// CV wrong (statically sized)
{
IsAContainer<const int> c;
IsAContainer<const volatile int> cv;
IsAContainer< volatile int> v;
std::span< int,1> s1{c}; // expected-error {{no matching constructor for initialization of 'std::span<int, 1>'}}
std::span< int,1> s2{v}; // expected-error {{no matching constructor for initialization of 'std::span<int, 1>'}}
std::span< int,1> s3{cv}; // expected-error {{no matching constructor for initialization of 'std::span<int, 1>'}}
std::span<const int,1> s4{v}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 1>'}}
std::span<const int,1> s5{cv}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 1>'}}
std::span< volatile int,1> s6{c}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 1>'}}
std::span< volatile int,1> s7{cv}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 1>'}}
}
}
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