[libcxx-commits] [libcxx] [libc++] Implement LWG3430 avoid implicit conversion of the source arguments to `std::filesystem::path` when constructing `std::basic_*fstream` (PR #85079)

[via libcxx-commits]

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@@ -21,11 +21,43 @@
 #include <fstream>
 #include <filesystem>
 #include <cassert>
+#include <type_traits>
+
 #include "test_macros.h"
+#include "test_iterators.h"
 #include "platform_support.h"
 
 namespace fs = std::filesystem;
 
+template <class CharT>
+constexpr bool test_non_convert_to_path() {
+  // String types
+  static_assert(!std::is_constructible_v<std::fstream, std::basic_string_view<CharT>>);
+  static_assert(!std::is_constructible_v<std::fstream, const std::basic_string_view<CharT>>);
+
+  // Char* pointers
+  if constexpr (!std::is_same_v<CharT, char>)
+    static_assert(!std::is_constructible_v<std::fstream, const CharT*>);
+
+  // Iterators
+  static_assert(!std::is_convertible_v<std::fstream, cpp17_input_iterator<const CharT*>>);
+
+  return true;
+}
+
+static_assert(test_non_convert_to_path<char>());
+
+#if !defined(TEST_HAS_NO_WIDE_CHARACTERS) && !defined(_LIBCPP_HAS_OPEN_WITH_WCHAR)
+static_assert(test_non_convert_to_path<wchar_t>());
+#endif // !TEST_HAS_NO_WIDE_CHARACTERS && !_LIBCPP_HAS_OPEN_WITH_WCHAR
+
+#if TEST_STD_VER > 17 && defined(__cpp_char8_t)
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yronglin wrote:

done

https://github.com/llvm/llvm-project/pull/85079