Added 3/4 of requested changes

AnabelSMRuggiero · Nov 22, 2021 · c702ec9 · c702ec9
1 parent bd56ca1
commit c702ec9
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/stl/inc/ranges b/stl/inc/ranges
@@ -3042,10 +3042,11 @@ namespace ranges {
         /* [[no_unique_address]] */ _Non_propagating_cache<_Cache_wrapper, false> _Inner{};
     };
 
-    // clang-format off
+
     template <class _Rng> // TRANSITION, LLVM-47414
-    concept _Can_const_join = input_range<const _Rng> && is_reference_v<range_reference_t<_Maybe_const<true, _Rng>>>;
+    concept _Can_const_join = input_range<const _Rng> && is_reference_v<range_reference_t<const _Rng>>;
 
+    // clang-format off
     template <class _Vw>
         requires is_reference_v<range_reference_t<_Vw>>
     class _Join_view_base<_Vw> : public view_interface<join_view<_Vw>> {};

diff --git a/tests/std/tests/P0896R4_views_join/test.cpp b/tests/std/tests/P0896R4_views_join/test.cpp
@@ -561,6 +561,14 @@ int main() {
         static_assert(ranges::distance(views::iota(0, 2) | views::transform(ToArrayOfImmovable) | views::join) == 6);
     }
 
+    { // Joining a non-const view without const qualified begin and end methods
+        vector<vector<size_t>> nested_vectors = {{0}, {1, 2, 3}, {99}, {4, 5, 6, 7}, {}, {8, 9, 10}};
+        auto RemoveSmallVectors       = [](const vector<size_t>& inner_vector) { return inner_vector.size() > 2; };
+        auto filted_and_joined        = nested_vectors | views::filter(RemoveSmallVectors) | views::join;
+        static constexpr int result[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        assert(ranges::equal(filted_and_joined, result));
+    }
+
     STATIC_ASSERT(instantiation_test());
     instantiation_test();
 }