feature/spaceship: Clause 23: Iterators (#1645)

Author: StephanTLavavej

stl/inc/iterator

@@ -302,11 +302,13 @@ _NODISCARD bool operator==(const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _
     return _Left._Equal(_Right);
 }
 
+#if !_HAS_CXX20
 template <class _Ty, class _Elem, class _Traits, class _Diff>
 _NODISCARD bool operator!=(const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Left,
     const istream_iterator<_Ty, _Elem, _Traits, _Diff>& _Right) noexcept /* strengthened */ {
     return !(_Left == _Right);
 }
+#endif // !_HAS_CXX20
 
 // CLASS TEMPLATE ostream_iterator
 template <class _Ty, class _Elem = char, class _Traits = char_traits<_Elem>>
@@ -488,11 +490,13 @@ _NODISCARD bool operator==(
     return _Left.equal(_Right);
 }
 
+#if !_HAS_CXX20
 template <class _Elem, class _Traits>
 _NODISCARD bool operator!=(
     const istreambuf_iterator<_Elem, _Traits>& _Left, const istreambuf_iterator<_Elem, _Traits>& _Right) {
     return !(_Left == _Right);
 }
+#endif // !_HAS_CXX20
 
 // CLASS TEMPLATE ostreambuf_iterator
 template <class _Elem, class _Traits>

tests/libcxx/expected_results.txt

@@ -671,6 +671,9 @@ std/utilities/memory/util.smartptr/util.smartptr.shared/libcxx.control_block_lay
 # Non-Standard assumption that std::filesystem::file_time_type::duration::period is std::nano
 std/input.output/filesystems/fs.filesystem.synopsis/file_time_type_resolution.compile.pass.cpp FAIL
 
+# P1614R2 "Adding Spaceship <=> To The Library" makes `std::operator!=(i1, i3)` an error
+std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp FAIL
+
 
 # *** LIKELY STL BUGS ***
 # Not yet analyzed, likely STL bugs. Assertions and other runtime failures.

tests/libcxx/skipped_tests.txt

@@ -671,6 +671,9 @@ utilities\memory\util.smartptr\util.smartptr.shared\libcxx.control_block_layout.
 # Non-Standard assumption that std::filesystem::file_time_type::duration::period is std::nano
 input.output\filesystems\fs.filesystem.synopsis\file_time_type_resolution.compile.pass.cpp
 
+# P1614R2 "Adding Spaceship <=> To The Library" makes `std::operator!=(i1, i3)` an error
+iterators\stream.iterators\istream.iterator\istream.iterator.ops\equal.pass.cpp
+
 
 # *** LIKELY STL BUGS ***
 # Not yet analyzed, likely STL bugs. Assertions and other runtime failures.