type computation in broadcast is worse than in map

[stevengj]

With current 0.5 master:

julia> map(Float32, [3,4,5])
3-element Array{Float32,1}:
 3.0
 4.0
 5.0

julia> broadcast(Float32, [3,4,5])
3-element Array{Int64,1}:
 3
 4
 5

We presumably want to return a Float32 array in both cases?

cc: @ViralBShah: this affects the case you asked about in #8450, since my f.(x...) implementation in #15032 is equivalent to broadcast.

[GunnarFarneback]

I believe this not really a type inference issue but a type computation issue due to a missing piece in the promote_op machinery.

[JeffBezanson]

I think broadcast is due for an update now that higher-order functions are fast.

[stevengj]

Another instance of the same problem: broadcast(sin, 3) throws an InexactError.

[stevengj]

See also #11119, #12277.

[stevengj]

Duplicate of #4883. (Yes, I duplicated my own issue. Sigh.)