In file included from ../arrow/cpp/src/arrow/ipc/dictionary.cc:32:
../arrow/cpp/src/arrow/record_batch.h:266:21: warning: ISO C++20 considers use of overloaded operator '==' (with operand types 'const Result<std::shared_ptr<RecordBatch>>' and 'const Result<std::shared_ptr<RecordBatch>>') to be ambiguous despite there being a unique best viable function [-Wambiguous-reversed-operator]
return batch_ == other.batch_;
~~~~~~ ^ ~~~~~~~~~~~~
../arrow/cpp/src/arrow/util/compare.h:54:8: note: ambiguity is between a regular call to this operator and a call with the argument order reversed
bool operator==(const T& other) const \{ return cast().Equals(other); }
^
In file included from ../arrow/cpp/src/arrow/ipc/dictionary.cc:18:
In file included from ../arrow/cpp/src/arrow/ipc/dictionary.h:27:
../arrow/cpp/src/arrow/result.h:278:20: warning: ISO C++20 considers use of overloaded operator '==' (with operand types 'const arrow::Status' and 'const arrow::Status') to be ambiguous despite there being a unique best viable function [-Wambiguous-reversed-operator]
return status_ == other.status_;
~~~~~~~ ^ ~~~~~~~~~~~~~
../arrow/cpp/src/arrow/util/compare.h:54:57: note: in instantiation of member function 'arrow::Result<std::shared_ptr<arrow::RecordBatch>>::Equals' requested here
bool operator==(const T& other) const \{ return cast().Equals(other); }
^
../arrow/cpp/src/arrow/record_batch.h:266:21: note: in instantiation of member function 'arrow::util::EqualityComparable<arrow::Result<std::shared_ptr<arrow::RecordBatch>>>::operator==' requested here
return batch_ == other.batch_;
^
../arrow/cpp/src/arrow/util/compare.h:54:8: note: ambiguity is between a regular call to this operator and a call with the argument order reversed
bool operator==(const T& other) const \{ return cast().Equals(other); }
^
2 warnings generated.
In file included from ../arrow/cpp/src/arrow/ipc/message.cc:33:
In file included from ../arrow/cpp/src/arrow/ipc/reader.h:32:
../arrow/cpp/src/arrow/record_batch.h:266:21: warning: ISO C++20 considers use of overloaded operator '==' (with operand types 'const Result<std::shared_ptr<RecordBatch>>' and 'const Result<std::shared_ptr<RecordBatch>>') to be ambiguous despite there being a unique best viable function [-Wambiguous-reversed-operator]
return batch_ == other.batch_;
~~~~~~ ^ ~~~~~~~~~~~~
../arrow/cpp/src/arrow/util/compare.h:54:8: note: ambiguity is between a regular call to this operator and a call with the argument order reversed
bool operator==(const T& other) const \{ return cast().Equals(other); }
^
In file included from ../arrow/cpp/src/arrow/ipc/message.cc:18:
In file included from ../arrow/cpp/src/arrow/ipc/message.h:30:
../arrow/cpp/src/arrow/result.h:278:20: warning: ISO C++20 considers use of overloaded operator '==' (with operand types 'const arrow::Status' and 'const arrow::Status') to be ambiguous despite there being a unique best viable function [-Wambiguous-reversed-operator]
return status_ == other.status_;
~~~~~~~ ^ ~~~~~~~~~~~~~
../arrow/cpp/src/arrow/util/compare.h:54:57: note: in instantiation of member function 'arrow::Result<std::shared_ptr<arrow::RecordBatch>>::Equals' requested here
bool operator==(const T& other) const \{ return cast().Equals(other); }
^
../arrow/cpp/src/arrow/record_batch.h:266:21: note: in instantiation of member function 'arrow::util::EqualityComparable<arrow::Result<std::shared_ptr<arrow::RecordBatch>>>::operator==' requested here
return batch_ == other.batch_;
^
../arrow/cpp/src/arrow/util/compare.h:54:8: note: ambiguity is between a regular call to this operator and a call with the argument order reversed
bool operator==(const T& other) const \{ return cast().Equals(other); }
Generate or hand written operator== for Result maybe fixing this problem. Seems problems cames from:
Xuwei Fu / @mapleFU:
@pitrou Hi, mind take a look? My fixing works for C+20, but would not compile in some platforms. Should I add some macros that make it only works in C+20?
When compiling arrow-9.0.0 in C++20, I got:
Generate or hand written
operator==
forResult
maybe fixing this problem. Seems problems cames from:https://stackoverflow.com/questions/65833022/inherited-synthesized-comparison-operator-produces-warning-error-iso-c20-cons
Reporter: Xuwei Fu / @mapleFU
PRs and other links:
Note: This issue was originally created as ARROW-17408. Please see the migration documentation for further details.