kszucs opened a new issue, #45816:
URL: https://github.com/apache/arrow/issues/45816
### Describe the enhancement requested
I was trying to use VisitType with a closure using the constexpr `type_id`
based type checkers from `type_traits` in the following fashion:
```cpp
auto handle_type = [&](auto&& type) {
using Type = std::decay_t<decltype(type)>;
if constexpr (::arrow::is_boolean(Type::type_id)) {
...
}
else if constexpr (::arrow::is_primitive(Type::type_id)) {
...
}
/* else etc. */
};
return VisitType(*values.type(), handle_type);
```
but got compile errors:
```
/Users/kszucs/Workspace/arrow/cpp/src/parquet/chunker_internal.cc:287:54:
error: no member named 'type_id' in 'arrow::DataType'
287 | if constexpr (::arrow::is_primitive(ArrowType::type_id)) {
| ^
/Users/kszucs/Workspace/arrow/cpp/src/arrow/visit_type_inline.h:88:10: note:
in instantiation of function template specialization
'parquet::internal::ContentDefinedChunker::Impl::GetChunks(const int16_t *,
const int16_t *, int64_t, const ::arrow::Array &)::(anonymous
class)::operator()<const arrow::DataType &>' requested here
88 | return std::forward<VISITOR>(visitor)(type,
std::forward<ARGS>(args)...);
| ^
/Users/kszucs/Workspace/arrow/cpp/src/parquet/chunker_internal.cc:299:21:
note: in instantiation of function template specialization
'arrow::VisitType<(lambda at
/Users/kszucs/Workspace/arrow/cpp/src/parquet/chunker_internal.cc:285:24) &>'
requested here
299 | return ::arrow::VisitType(*values.type(), handle_type);
| ^
```
because of the fallback branch (which is also mentioned in the docstrings):
https://github.com/apache/arrow/blob/bc0b8585f8807a2e41d7484343cc2e9924c84f51/cpp/src/arrow/visit_type_inline.h#L69-L89
Since the base `DataType` doesn't define `type_id` we cannot use this
dispatching pattern with the constexpr type checking functions.
### Component(s)
C++
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