[libcxx-commits] [libcxx] [libc++] Fix {deque, vector}::append_range assuming too much about the types (PR #162438)

[Louis Dionne via libcxx-commits]

================
@@ -643,6 +643,62 @@ constexpr void test_sequence_assign_range_move_only() {
   c.assign_range(in);
 }
 
+struct InPlaceOnly {
+  constexpr InPlaceOnly() {}
+  InPlaceOnly(const InPlaceOnly&) = delete;
+  InPlaceOnly(InPlaceOnly&&) = delete;
+  InPlaceOnly& operator=(const InPlaceOnly&) = delete;
+  InPlaceOnly& operator=(InPlaceOnly&&) = delete;
+};
+
+struct EmplaceConstructible {
+  EmplaceConstructible(const EmplaceConstructible&) = delete;
+  EmplaceConstructible& operator=(const EmplaceConstructible&) = delete;
+  EmplaceConstructible& operator=(EmplaceConstructible&&) = delete;
+  EmplaceConstructible(EmplaceConstructible&&) = delete;
+  constexpr EmplaceConstructible(const InPlaceOnly&) {}
+};
+
+template <template <class...> class Container>
+constexpr void test_sequence_append_range_emplace_constructible() {
+  InPlaceOnly input[5];
+  types::for_each(types::cpp20_input_iterator_list<InPlaceOnly*>{}, [&]<class Iter> {
+    std::ranges::subrange in(Iter(input), sentinel_wrapper<Iter>(Iter(input + 5)));
+    Container<EmplaceConstructible> c;
+    c.append_range(in);
+  });
+}
+
+template <template <class...> class Container>
+constexpr void test_sequence_prepend_range_emplace_constructible() {
+  InPlaceOnly input[5];
+  types::for_each(types::cpp20_input_iterator_list<InPlaceOnly*>{}, [&]<class Iter> {
+    std::ranges::subrange in(Iter(input), sentinel_wrapper<Iter>(Iter(input + 5)));
+    Container<EmplaceConstructible> c;
+    c.prepend_range(in);
+  });
+}
+
+// vector has a special requirement that the type also has to be Cpp17MoveInsertable
+
----------------
ldionne wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/162438