[clang] [clang-tools-extra] [libcxx] [llvm] [libc++] implement views::concat (PR #120920)

[A. Jiang via llvm-commits]

================
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+#include <ranges>
+#include <vector>
+
+#include <cassert>
+#include "test_iterators.h"
+
+constexpr void general_tests() {
+  std::vector<int> v1 = {1, 2, 3, 4, 5, 6, 7, 8};
+  std::vector<int> v2 = {1, 2, 3, 4, 5, 6, 7, 8};
+  using type          = std::vector<int>;
----------------
frederick-vs-ja wrote:

Ditto unused typedef-names.
```suggestion
```

https://github.com/llvm/llvm-project/pull/120920