[libcxx-commits] [libcxx] [libc++][ranges] P2116R9: Implements `views::enumerate` (PR #73617)

[Konstantin Varlamov via libcxx-commits]

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@@ -0,0 +1,136 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_ENUMERATE_TYPES_H
+#define TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_ENUMERATE_TYPES_H
+
+#include <ranges>
+
+#include "test_iterators.h"
+#include "test_macros.h"
+
+// Types
+
+struct RangeView : std::ranges::view_base {
+  using Iterator = cpp20_input_iterator<int*>;
+  using Sentinel = sentinel_wrapper<Iterator>;
+
+  constexpr explicit RangeView(int* b, int* e) : begin_(b), end_(e) {}
+  constexpr RangeView(RangeView const& other) : begin_(other.begin_), end_(other.end_), wasCopyInitialized(true) {}
+  constexpr RangeView(RangeView&& other) : begin_(other.begin_), end_(other.end_), wasMoveInitialized(true) {}
+  RangeView& operator=(RangeView const&) = default;
+  RangeView& operator=(RangeView&&)      = default;
+
+  constexpr int* begin() const { return begin_; }
+  constexpr int* end() const { return end_; }
+
+  int* begin_;
+  int* end_;
+
+  bool wasCopyInitialized = false;
+  bool wasMoveInitialized = false;
+};
+
+LIBCPP_STATIC_ASSERT(std::ranges::__range_with_movable_references<RangeView>);
+static_assert(std::ranges::range<RangeView>);
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var-const wrote:

Nit: the `view` concept subsumes `range`, so this check is redundant (due to the `view` check immediately below). Applies below as well.

https://github.com/llvm/llvm-project/pull/73617