Re: [PATCH] libstdc++: Avoid accidental ADL when calling make_reverse_iterator

[Jonathan Wakely via Gcc-patches]

On 23/03/21 18:45 +0100, Moritz Sichert via Libstdc++ wrote:

Thank you!

You are right. The idea was that the test also tests the const overloads of 
begin() and end() of reverse_view. But the view concept requires movable. 
Maybe, this should just be

static_assert(std::ranges::range<const decltype(v)>);

instead?

Oops, I mean to delete the second line, not just the 'const' keyword.
But checking that it models range is better.

Also the comment is slightly wrong, it won't call
make_reserve_iterator(const A&) it will call make_reserve_iterator(A*)
or make_reserve_iterator(const A*).

I've committed the attached patch. Thanks again.



commit d1aa5f57db7c14a62e9b7e2a2aa8a9c402a89363
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Tue Mar 23 18:22:18 2021

    libstdc++: Improve test for views::reverse
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/std/ranges/adaptors/reverse.cc: Replace duplicated
            line with a check that uses the const being/end overloads.

diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/reverse.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/reverse.cc
index 47386575192..0d52498e207 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/reverse.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/reverse.cc
@@ -141,11 +141,12 @@ namespace test_ns
 void test06()
 {
   // Check that views::reverse works and does not use ADL which could lead
-  // to accidentally finding test_ns::make_reverse_iterator(const A&).
+  // to accidentally finding test_ns::make_reverse_iterator(A*).
   test_ns::A as[] = {{}, {}};
   auto v = as | std::views::reverse;
-  static_assert(std::ranges::view<decltype(v)>);
-  static_assert(std::ranges::view<decltype(v)>);
+  using V = decltype(v);
+  static_assert( std::ranges::view<V> );
+  static_assert( std::ranges::range<const V> );
 }
 
 int