Implement promotion rules for CategoricalArray
#384
Merged
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These are rarely needed, but an exception is when storing
CategoricalArray
objects within arrays, as the[a1, a2]
syntax uses promotion to choose the element type of the result. This previously failed as it hit a fallbackpromote_result
method defined forAbstractArray
in Base in range.jl, which tried to convertCategoricalArray
s toArray
by calling nonexistentconvert
methods forCategoricalValue
.Fixes #383.