[libc++] fix flat_{multi}set insert_range

Author: huixie90

libcxx/include/__flat_set/utils.h

@@ -11,6 +11,7 @@
 #define _LIBCPP___FLAT_SET_UTILS_H
 
 #include <__config>
+#include <__iterator/iterator_traits.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
 #include <__type_traits/container_traits.h>
@@ -60,7 +61,8 @@ struct __flat_set_utils {
       // C++23 Sequence Container should have insert_range member function
       // Note that not all Sequence Containers provide append_range.
       __set.__keys_.insert_range(__set.__keys_.end(), std::forward<_Range>(__rng));
-    } else if constexpr (ranges::common_range<_Range>) {
+    } else if constexpr (ranges::common_range<_Range> &&
+                         __has_input_iterator_category<ranges::iterator_t<_Range>>::value) {
       __set.__keys_.insert(__set.__keys_.end(), ranges::begin(__rng), ranges::end(__rng));
     } else {
       for (auto&& __x : __rng) {

libcxx/test/std/containers/container.adaptors/flat.multiset/flat.multiset.modifiers/insert_range.pass.cpp

@@ -18,6 +18,7 @@
 #include <flat_set>
 #include <functional>
 #include <ranges>
+#include <sstream>
 #include <vector>
 
 #include "MinSequenceContainer.h"
@@ -85,6 +86,15 @@ void test() {
     MoveOnly expected[] = {1, 1, 3, 4, 5};
     assert(std::ranges::equal(m, expected));
   }
+  {
+    // https://github.com/llvm/llvm-project/issues/136656
+    MinSequenceContainer<int> v;
+    std::flat_multiset s(v);
+    std::istringstream ints("0 1 1 0");
+    auto r = std::ranges::subrange(std::istream_iterator<int>(ints), std::istream_iterator<int>()) |
+             std::views::transform([](int i) { return i * i; });
+    s.insert_range(r);
+  }
 }
 
 void test_exception() {

libcxx/test/std/containers/container.adaptors/flat.set/flat.set.modifiers/insert_range.pass.cpp

@@ -18,6 +18,7 @@
 #include <flat_set>
 #include <functional>
 #include <ranges>
+#include <sstream>
 #include <vector>
 
 #include "MinSequenceContainer.h"
@@ -96,6 +97,15 @@ void test() {
     MoveOnly expected[] = {1, 3, 4, 5};
     assert(std::ranges::equal(m, expected));
   }
+  {
+    // https://github.com/llvm/llvm-project/issues/136656
+    MinSequenceContainer<int> v;
+    std::flat_set s(v);
+    std::istringstream ints("0 1 1 0");
+    auto r = std::ranges::subrange(std::istream_iterator<int>(ints), std::istream_iterator<int>()) |
+             std::views::transform([](int i) { return i * i; });
+    s.insert_range(r);
+  }
 }
 
 void test_exception() {