[libcxx-commits] [libcxx] [libc++] LWG 3987 provide iterator.range access from flat_{map, set} (PR #137524)

[A. Jiang via libcxx-commits]

================
@@ -0,0 +1,184 @@
+# ===----------------------------------------------------------------------===##
+#
+# 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
+#
+# ===----------------------------------------------------------------------===##
+
+# In addition to being available via inclusion of the <iterator> header,
+# the function templates in [iterator.range] are available when any of the following
+# headers are included: <array>, <deque>, <flat_map>, <flat_set>, <forward_list>,
+# <list>, <map>, <regex>, <set>, <span>, <string>, <string_view>, <unordered_map>,
+# <unordered_set>, <vector>.
+
+# RUN: %{python} %s %{libcxx-dir}/utils
+# END.
+
+import sys
+
+sys.path.append(sys.argv[1])
+from libcxx.header_information import (
+    lit_header_restrictions,
+    lit_header_undeprecations,
+    Header,
+)
+
+headers = list(
+    map(
+        Header,
+        [
+            "array",
+            "deque",
+            "flat_map",
+            "flat_set",
+            "forward_list",
+            "list",
+            "map",
+            "regex",
+            "set",
+            "span",
+            "string",
+            "string_view",
+            "unordered_map",
+            "unordered_set",
+            "vector",
+        ],
+    )
+)
+
+for header in headers:
+    print(
+        f"""\
+//--- {header}.pass.cpp
+{lit_header_restrictions.get(header, '')}
+{lit_header_undeprecations.get(header, '')}
+// UNSUPPORTED: clang-modules-build
+// UNSUPPORTED: c++03
+
+// Some of the functions' return type, reverse_iterator, is not exported from
+// these headers, so we need to include <iterator> explicitly, which defeats
+// the purpose of this test. So disable the test for clang modules.
+
+#include <{header}>
+#include <cassert>
+
+#include "test_macros.h"
+
+struct Container {{
+  int a[3] = {{1, 2, 3}};
+
+  int* begin() {{ return &a[0]; }}
+  const int* begin() const {{ return &a[0]; }}
+  int* rbegin() {{ return &a[2]; }}
+  const int* rbegin() const {{ return &a[2]; }}
+  int* end() {{ return &a[3]; }}
+  const int* end() const {{ return &a[3]; }}
+  int* rend() {{ return (&a[0]) - 1; }}
+  const int* rend() const {{ return (&a[0]) - 1; }}
+  std::size_t size() const {{ return 3; }}
+  bool empty() const {{ return false; }}
+  int* data() {{return &a[0]; }}
+  const int* data() const {{ return &a[0]; }}
+}};
+
+int main(int, char**)  {{
+  {{
----------------
frederick-vs-ja wrote:

I submitted [LWG3623](https://cplusplus.github.io/LWG/issue3623) for the availability of `reverse_iterator` years ago. But the issue seems ignored for a long while.

https://github.com/llvm/llvm-project/pull/137524