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
10 // UNSUPPORTED: libcpp-no-concepts
11 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
12 
13 // template<class R>
14 //   explicit join_view(R&&) -> join_view<views::all_t<R>>;
15 
16 // Tests that the deduction guide is explicit.
17 
18 #include <ranges>
19 
20 #include "test_iterators.h"
21 
22 template<class T>
23 struct Range {
24   friend T* begin(Range&) { return nullptr; }
25   friend T* begin(Range const&) { return nullptr; }
26   friend sentinel_wrapper<T*> end(Range&) { return sentinel_wrapper<T*>(nullptr); }
27   friend sentinel_wrapper<T*> end(Range const&) { return sentinel_wrapper<T*>(nullptr); }
28 };
29 
30 void testExplicitCTAD() {
31   Range<Range<int>> r;
32   std::ranges::join_view v = r; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'join_view'}}
33 }
34