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//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <optional>
// UNSUPPORTED: c++98, c++03, c++11, c++14
// UNSUPPORTED: clang-5
// UNSUPPORTED: libcpp-no-deduction-guides
// Clang 5 will generate bad implicit deduction guides
// Specifically, for the copy constructor.
// template<class T>
// optional(T) -> optional<T>;
#include <optional>
#include <cassert>
struct A {};
int main()
{
// Test the explicit deduction guides
// Test the implicit deduction guides
{
// optional()
std::optional opt; // expected-error-re {{{{declaration of variable 'opt' with deduced type 'std::optional' requires an initializer|no viable constructor or deduction guide for deduction of template arguments of 'optional'}}}}
// clang-6 gives a bogus error here:
// declaration of variable 'opt' with deduced type 'std::optional' requires an initializer
// clang-7 (and later) give a better message:
// no viable constructor or deduction guide for deduction of template arguments of 'optional'
// So we check for one or the other.
}
{
// optional(nullopt_t)
std::optional opt(std::nullopt); // expected-error-re@optional:* {{static_assert failed{{.*}} "instantiation of optional with nullopt_t is ill-formed"}}
}
}
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