There was quite some discussion on this topic in https://groups.google.com/forum/?fromgroups=#!searchin/julia-users/Int32/julia-users/Rte_I6htLRc/VJG5DWVcZbQJ I had the feeling that we almost convinced Stefan :-)
The good thing is that Array{Int32} operations do not promote to
Array{Int64}. But I still vote for promoting Int32 + Int32 to Int32.
