See also
https://github.com/JuliaLang/julia/issues/10154
where a lot of this was discussed.
Non-integer indices often indicate a mistake on the part of the programmer
(e.g. using / rather than ÷, i.e. div), and it is more reliable to force
the programmer to be explicit about what was intended (both to indicate
whether they want round/floor/ceil, and to correct unintentional type
instabilities that often accrue from accidental floating-point indices).
It is also a headache for people implementing AbstractArray subtypes,
because it creates an expectation that they will implement non-obvious
getindex methods for Real types, with calls to the to_index method as
needed.
I feel like 99% of the problems that people have with deprecating
floating-point indices arise because they used / rather than ÷ for an
integer division. I wonder if there is some way to give a helpful warning
in such cases?
