[PATCH] libstdc++: Fix typo in views::as_const's operator() [PR109525]

[Patrick Palka via Gcc-patches]

        PR libstdc++/109525

libstdc++-v3/ChangeLog:

        * include/std/ranges (views::_AsConst::operator()): Add
        missing const to constant_range test.
        * testsuite/std/ranges/adaptors/as_const/1.cc (test02):
        Improve formatting.  Adjust expected type of v2.
        (test03): New test.
---
 libstdc++-v3/include/std/ranges               |  2 +-
 .../std/ranges/adaptors/as_const/1.cc         | 37 ++++++++++++-------
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 283d757faa4..1714f3fb16c 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -9025,7 +9025,7 @@ namespace views::__adaptor
          return ref_view(static_cast<const element_type&>
                          (std::forward<_Range>(__r).base()));
        else if constexpr (is_lvalue_reference_v<_Range>
-                          && constant_range<_Tp>
+                          && constant_range<const _Tp>
                           && !view<_Tp>)
          return ref_view(static_cast<const _Tp&>(__r));
        else
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/as_const/1.cc 
b/libstdc++-v3/testsuite/std/ranges/adaptors/as_const/1.cc
index d04645f047e..ac1be7440e4 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/as_const/1.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/as_const/1.cc
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <span>
 #include <utility>
+#include <vector>
 #include <testsuite_hooks.h>
 #include <testsuite_iterators.h>
 
@@ -36,29 +37,37 @@ test01()
 constexpr bool
 test02()
 {
-  std::same_as<ranges::empty_view<const int>> auto v1
-    = views::empty<int> | views::as_const;
-
   int x[] = {1, 2, 3};
-  std::same_as<ranges::as_const_view<ranges::ref_view<int[3]>>> auto v2
-    = x | views::as_const;
-  std::same_as<ranges::ref_view<const int[3]>> auto v3
-    = std::as_const(x) | views::as_const;
-  std::same_as<ranges::ref_view<const int[3]>> auto v4
-    = std::as_const(x) | views::all | views::as_const;
-  std::same_as<std::span<const int>> auto v5
-    = std::span{x, x+3} | views::as_const;
-
-  
std::same_as<ranges::as_const_view<ranges::chunk_view<ranges::ref_view<int[3]>>>>
 auto v6
-     = x | views::chunk(2) | views::as_const;
+  std::same_as<ranges::empty_view<const int>>
+    auto v1 = views::empty<int> | views::as_const;
+  std::same_as<ranges::ref_view<const int[3]>>
+    auto v2 = x | views::as_const;
+  std::same_as<ranges::ref_view<const int[3]>>
+    auto v3 = std::as_const(x) | views::as_const;
+  std::same_as<ranges::ref_view<const int[3]>>
+    auto v4 = std::as_const(x) | views::all | views::as_const;
+  std::same_as<std::span<const int>>
+    auto v5 = std::span{x, x+3} | views::as_const;
+  
std::same_as<ranges::as_const_view<ranges::chunk_view<ranges::ref_view<int[3]>>>>
+    auto v6 = x | views::chunk(2) | views::as_const;
   VERIFY( v6.size() == 2 );
 
   return true;
 }
 
+void
+test03()
+{
+  // PR libstdc++/109525
+  std::vector<int> v;
+  std::same_as<ranges::ref_view<const std::vector<int>>>
+    auto r = views::as_const(v);
+}
+
 int
 main()
 {
   static_assert(test01());
   static_assert(test02());
+  test03();
 }
-- 
2.40.0.335.g9857273be0