clarify lack of operator-> for std::counted_iterator adapting collect…

…ion iterators
AIDASoft · Jun 12, 2024 · cc18f02 · cc18f02
1 parent 38a014f
commit cc18f02
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diff --git a/doc/collections_as_container.md b/doc/collections_as_container.md
@@ -167,8 +167,8 @@ In addition to the *LegacyForwardIterator* the C++ standard specifies also the *
 | `std::front_insert_iterator` | ❌ no | `push_front` not defined |
 | `std::insert_iterator` | ❌ no | `insert` not defined |
 | `std::const_iterator` (C++23) | ❌ no | C++23 not supported yet |
-| `std::move_iterator` | ✔️ yes | Limited usefulness since dereference returns `reference` not rvalue (`&&`) |
-| `std::counted_iterator` | ✔️ yes | |
+| `std::move_iterator` | ✔️ yes | Limited usefulness since dereference returns `reference` type not rvalue reference (`&&`) |
+| `std::counted_iterator` | ✔️ yes | `operator->` not defined as it requires `std::contiguous_iterator` |
 
 
 ## Collection and standard algorithms

diff --git a/tests/unittests/std_interoperability.cpp b/tests/unittests/std_interoperability.cpp
@@ -1117,6 +1117,11 @@ TEST_CASE("Collection and std iterator adaptors", "[collection][container][adapt
       REQUIRE(counted != std::default_sentinel);
       REQUIRE(counted.count() == 1);
       REQUIRE((*counted).cellID() == 42);
+      DOCUMENTED_STATIC_FAILURE(std::contiguous_iterator<iterator>); // counted-> requires std::contiguous_iterator
+      // REQUIRE(counted->cellID() == 42);
+      DOCUMENTED_STATIC_FAILURE(traits::has_member_of_pointer_v<const iterator>); // can't base()->() because
+                                                                                  // base() returns const object
+      // REQUIRE(counted.base()->cellID() == 42);
       REQUIRE(++counted == std::default_sentinel);
     }
     // const_iterator
@@ -1128,6 +1133,11 @@ TEST_CASE("Collection and std iterator adaptors", "[collection][container][adapt
       REQUIRE(counted != std::default_sentinel);
       REQUIRE(counted.count() == 1);
       REQUIRE((*counted).cellID() == 42);
+      DOCUMENTED_STATIC_FAILURE(std::contiguous_iterator<iterator>); // counted-> requires std::contiguous_iterator
+      // REQUIRE(counted->cellID() == 42)
+      DOCUMENTED_STATIC_FAILURE(traits::has_member_of_pointer_v<const const_iterator>); // can't base()->() because
+                                                                                        // base() returns const object
+      // REQUIRE(counted.base()->cellID() == 42);
       REQUIRE(++counted == std::default_sentinel);
     }
   }