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 11 // <ranges> 12 13 // template<class T> 14 // inline constexpr bool enable_view = ...; 15 16 #include <ranges> 17 18 #include "test_macros.h" 19 20 // Doesn't derive from view_base 21 struct Empty { }; 22 static_assert(!std::ranges::enable_view<Empty>); 23 static_assert(!std::ranges::enable_view<Empty&>); 24 static_assert(!std::ranges::enable_view<Empty&&>); 25 static_assert(!std::ranges::enable_view<const Empty>); 26 static_assert(!std::ranges::enable_view<const Empty&>); 27 static_assert(!std::ranges::enable_view<const Empty&&>); 28 29 // Derives from view_base, but privately 30 struct PrivateViewBase : private std::ranges::view_base { }; 31 static_assert(!std::ranges::enable_view<PrivateViewBase>); 32 static_assert(!std::ranges::enable_view<PrivateViewBase&>); 33 static_assert(!std::ranges::enable_view<PrivateViewBase&&>); 34 static_assert(!std::ranges::enable_view<const PrivateViewBase>); 35 static_assert(!std::ranges::enable_view<const PrivateViewBase&>); 36 static_assert(!std::ranges::enable_view<const PrivateViewBase&&>); 37 38 // Derives from view_base, but specializes enable_view to false 39 struct EnableViewFalse : std::ranges::view_base { }; 40 template <> constexpr bool std::ranges::enable_view<EnableViewFalse> = false; 41 static_assert(!std::ranges::enable_view<EnableViewFalse>); 42 static_assert(!std::ranges::enable_view<EnableViewFalse&>); 43 static_assert(!std::ranges::enable_view<EnableViewFalse&&>); 44 static_assert(std::ranges::enable_view<const EnableViewFalse>); 45 static_assert(!std::ranges::enable_view<const EnableViewFalse&>); 46 static_assert(!std::ranges::enable_view<const EnableViewFalse&&>); 47 48 // Derives from view_base 49 struct PublicViewBase : std::ranges::view_base { }; 50 static_assert(std::ranges::enable_view<PublicViewBase>); 51 static_assert(!std::ranges::enable_view<PublicViewBase&>); 52 static_assert(!std::ranges::enable_view<PublicViewBase&&>); 53 static_assert(std::ranges::enable_view<const PublicViewBase>); 54 static_assert(!std::ranges::enable_view<const PublicViewBase&>); 55 static_assert(!std::ranges::enable_view<const PublicViewBase&&>); 56 57 // Does not derive from view_base, but specializes enable_view to true 58 struct EnableViewTrue { }; 59 template <> constexpr bool std::ranges::enable_view<EnableViewTrue> = true; 60 static_assert(std::ranges::enable_view<EnableViewTrue>); 61 static_assert(!std::ranges::enable_view<EnableViewTrue&>); 62 static_assert(!std::ranges::enable_view<EnableViewTrue&&>); 63 static_assert(!std::ranges::enable_view<const EnableViewTrue>); 64 static_assert(!std::ranges::enable_view<const EnableViewTrue&>); 65 static_assert(!std::ranges::enable_view<const EnableViewTrue&&>); 66 67 // Make sure that enable_view is a bool, not some other contextually-convertible-to-bool type. 68 ASSERT_SAME_TYPE(decltype(std::ranges::enable_view<Empty>), const bool); 69 ASSERT_SAME_TYPE(decltype(std::ranges::enable_view<PublicViewBase>), const bool); 70 71 struct V1 : std::ranges::view_interface<V1> {}; 72 static_assert(std::ranges::enable_view<V1>); 73 static_assert(!std::ranges::enable_view<V1&>); 74 static_assert(!std::ranges::enable_view<V1&&>); 75 static_assert(std::ranges::enable_view<const V1>); 76 static_assert(!std::ranges::enable_view<const V1&>); 77 static_assert(!std::ranges::enable_view<const V1&&>); 78 79 struct V2 : std::ranges::view_interface<V1>, std::ranges::view_interface<V2> {}; 80 static_assert(!std::ranges::enable_view<V2>); 81 static_assert(!std::ranges::enable_view<V2&>); 82 static_assert(!std::ranges::enable_view<V2&&>); 83 static_assert(!std::ranges::enable_view<const V2>); 84 static_assert(!std::ranges::enable_view<const V2&>); 85 static_assert(!std::ranges::enable_view<const V2&&>); 86 87 struct V3 : std::ranges::view_interface<V1> {}; 88 static_assert(std::ranges::enable_view<V3>); 89 static_assert(!std::ranges::enable_view<V3&>); 90 static_assert(!std::ranges::enable_view<V3&&>); 91 static_assert(std::ranges::enable_view<const V3>); 92 static_assert(!std::ranges::enable_view<const V3&>); 93 static_assert(!std::ranges::enable_view<const V3&&>); 94 95 struct PrivateInherit : private std::ranges::view_interface<PrivateInherit> {}; 96 static_assert(!std::ranges::enable_view<PrivateInherit>); 97 98 // ADL-proof 99 struct Incomplete; 100 template<class T> struct Holder { T t; }; 101 static_assert(!std::ranges::enable_view<Holder<Incomplete>*>); 102 103 static_assert(!std::ranges::enable_view<void>); 104