Ben Kietzman created ARROW-11509:
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             Summary: [C++][Compute] Overhaul CanCast() helper function
                 Key: ARROW-11509
                 URL: https://issues.apache.org/jira/browse/ARROW-11509
             Project: Apache Arrow
          Issue Type: Bug
          Components: C++
    Affects Versions: 3.0.0
            Reporter: Ben Kietzman


{\{CanCast(const DataType& from, const DataType& to)}} is intended to return 
true iff a cast can be made between the provided types. Since it currently only 
consults the type_id of the types and the kernels implementing the casts, it 
will return true for some unsupported casts. For example: 
{{CanCast(*list(null()), *list(list(int32())))}} currently returns true, even 
though that cast is not supported. It would also be useful to provide an 
overloads to specify  restrictions on a cast; for example \{{CanCast(int32(), 
int8(), guaranteed_safe)}} would return false since int32 may overflow when 
cast to int8



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