libcxx/test/std/ranges/range.utility/range.utility.conv/from_range_t.compile.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
  10
  11 // struct from_range_t { explicit from_range_t() = default; };  // Since C++23
  12 // inline constexpr from_range_t from_range{};                  // Since C++23
  13
  14 #include <ranges>
  15
  16 template <class T>
  17 void check(std::from_range_t);
  18
  19 template <class T>
  20 concept IsCtrNonexplicit = requires {
  21   check<T>({});
  22 };
  23
  24 // Verify that the constructor is `explicit`.
  25 static_assert(!IsCtrNonexplicit<std::from_range_t>);