At the moment, the result's element type of broadcast is determined in a straight-forward way by typejoining the type of all the result's elements. (Exception: The empty case, where inference is invoked.) However, for certain operations, the more elaborate mechanism of promote_op is used, which especially aims at doing magical stuff if the input arrays have non-leaf element types. E.g.

julia> x = ones(Real, 1)
1-element Array{Real,1}:
 1

julia> x .+ x
1-element Array{Int64,1}:
 2

julia> x + x
1-element Array{Real,1}:
 2

While the behavior of + here does look useful, I wonder whether it is worth the inconsistency and the effort. I tend to say no, but before starting any real work on the issue, I'd like some feedback.