GH-45816: [C++] Make VisitType()
fallback branch unreachable
#45815
+2
−2
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Rationale for this change
Enable using the more convenient
constexpr
type checking functions fromtype_traits
withVisitType
dispatchers, like:What changes are included in this PR?
Remove the fallback call with
const DataType&
rather make the default branch unreachable at compile time.Are these changes tested?
Yes,
VisitType
is being used at multiple places in the codebase.Are there any user-facing changes?
Yes, this is a breaking change. The visitor passed to
VisitType
doesn't need to have an implementation for the baseDataType
.VisitType()
requires the visitor to have in implementation for baseDataType
#45816