[libcxx-commits] [libcxx] [libc++][ranges] Fix `ranges::join_view` segmented iterator trait (PR #158347)

[Nikolas Klauser via libcxx-commits]

================
@@ -272,57 +272,89 @@ class Comparable {
   friend bool operator==(const Comparable& lhs, long long rhs) { return comparable_data[lhs.index_] == rhs; }
 };
 
-void test_deque() {
-  { // empty deque
-    std::deque<int> data;
-    assert(std::ranges::find(data, 4) == data.end());
-    assert(std::ranges::find(data.begin(), data.end(), 4) == data.end());
-  }
-
-  { // single element - match
-    std::deque<int> data = {4};
-    assert(std::ranges::find(data, 4) == data.begin());
-    assert(std::ranges::find(data.begin(), data.end(), 4) == data.begin());
-  }
-
-  { // single element - no match
-    std::deque<int> data = {3};
-    assert(std::ranges::find(data, 4) == data.end());
-    assert(std::ranges::find(data.begin(), data.end(), 4) == data.end());
-  }
-
-  // many elements
-  for (auto size : {2, 3, 1023, 1024, 1025, 2047, 2048, 2049}) {
-    { // last element match
+void test_segmented_iterator_types() {
+  // deque
+  {
+    { // empty deque
       std::deque<int> data;
-      data.resize(size);
-      std::fill(data.begin(), data.end(), 3);
-      data[size - 1] = 4;
-      assert(std::ranges::find(data, 4) == data.end() - 1);
-      assert(std::ranges::find(data.begin(), data.end(), 4) == data.end() - 1);
+      assert(std::ranges::find(data, 4) == data.end());
+      assert(std::ranges::find(data.begin(), data.end(), 4) == data.end());
     }
 
-    { // second-last element match
-      std::deque<int> data;
-      data.resize(size);
-      std::fill(data.begin(), data.end(), 3);
-      data[size - 2] = 4;
-      assert(std::ranges::find(data, 4) == data.end() - 2);
-      assert(std::ranges::find(data.begin(), data.end(), 4) == data.end() - 2);
+    { // single element - match
+      std::deque<int> data = {4};
+      assert(std::ranges::find(data, 4) == data.begin());
+      assert(std::ranges::find(data.begin(), data.end(), 4) == data.begin());
     }
 
-    { // no match
-      std::deque<int> data;
-      data.resize(size);
-      std::fill(data.begin(), data.end(), 3);
+    { // single element - no match
+      std::deque<int> data = {3};
       assert(std::ranges::find(data, 4) == data.end());
       assert(std::ranges::find(data.begin(), data.end(), 4) == data.end());
     }
+
+    // many elements
+    for (auto size : {2, 3, 1023, 1024, 1025, 2047, 2048, 2049}) {
+      { // last element match
+        std::deque<int> data;
+        data.resize(size);
+        std::fill(data.begin(), data.end(), 3);
+        data[size - 1] = 4;
+        assert(std::ranges::find(data, 4) == data.end() - 1);
+        assert(std::ranges::find(data.begin(), data.end(), 4) == data.end() - 1);
+      }
+
+      { // second-last element match
+        std::deque<int> data;
+        data.resize(size);
+        std::fill(data.begin(), data.end(), 3);
+        data[size - 2] = 4;
+        assert(std::ranges::find(data, 4) == data.end() - 2);
+        assert(std::ranges::find(data.begin(), data.end(), 4) == data.end() - 2);
+      }
+
+      { // no match
+        std::deque<int> data;
+        data.resize(size);
+        std::fill(data.begin(), data.end(), 3);
+        assert(std::ranges::find(data, 4) == data.end());
+        assert(std::ranges::find(data.begin(), data.end(), 4) == data.end());
+      }
+    }
+  }
+  // join_view
+  // See https://llvm.org/PR158279
----------------
philnik777 wrote:

Please add a proper description.

https://github.com/llvm/llvm-project/pull/158347