[PATCH] Activate __cpp_lib_ranges_to_container test

[François Dumont]

Hi

Now that __cpp_lib_ranges_to_container support have been added to 
std::set we can activate those checks.

    libstdc++: Activate a __cpp_lib_ranges_to_container dependent test

    Now that std::set has support for __cpp_lib_ranges_to_container we can
    activate a test using it in a fancy allocator pointer context.

    libstdc++-v3/ChangeLog

            * 
testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc:
            Activate the template member tests involving 
__cpp_lib_ranges_to_container
            support.

Tested under Linux x64, ok to commit ?

François
diff --git 
a/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc
 
b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc
index 4fa84a74882..575d5901496 100644
--- 
a/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc
+++ 
b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc
@@ -76,14 +76,12 @@ test_template_members(__gnu_test::input_container<short>& c)
   s.merge(m1);
 #endif
 
-#if 0
 #ifdef __cpp_lib_ranges_to_container
   short arr[2];
   __gnu_test::test_input_range<short> r(arr);
   std::set<int, std::less<int>, Allocator<int>> s2(std::from_range, r);
   std::set<int, std::less<int>, Allocator<int>> s3(std::from_range, r,
                                                   Allocator<int>{});
-  s2.insert_range(s2.begin(), r);
-#endif
+  s2.insert_range(r);
 #endif
 }