Merge pull request JuliaLang#4741 from simonster/broadcast-workaround

Incomplete fix/workaround for broadcast static type inference (JuliaLang#4673)

base/broadcast.jl

@@ -8,13 +8,24 @@ export broadcast_getindex, broadcast_setindex!
 
 ## Broadcasting utilities ##
 
+droparg1(a, args...) = args
+
+longer_tuple(x::(), retx::Tuple, y::(), rety::Tuple) = retx
+longer_tuple(x::(), retx::Tuple, y::Tuple, rety::Tuple) = rety
+longer_tuple(x::Tuple, retx::Tuple, y::(), rety::Tuple) = retx
+longer_tuple(x::Tuple, retx::Tuple, y::Tuple, rety::Tuple) =
+ longer_tuple(droparg1(x...), retx, droparg1(y...), rety)
+longer_tuple(x::Tuple, y::Tuple) = longer_tuple(x, x, y, y)
+
+longer_size(x::AbstractArray) = size(x)
+longer_size(x::AbstractArray, y::AbstractArray...) =
+ longer_tuple(size(x), longer_size(y...))
+
 # Calculate the broadcast shape of the arguments, or error if incompatible
 broadcast_shape() = ()
 function broadcast_shape(As::AbstractArray...)
- nd = ndims(As[1])
- for i = 2:length(As)
- nd = max(nd, ndims(As[i]))
- end
+ sz = longer_size(As...)
+ nd = length(sz)
  bshape = ones(Int, nd)
  for A in As
  for d = 1:ndims(A)
@@ -28,7 +39,7 @@ function broadcast_shape(As::AbstractArray...)
  end
  end
  end
- return tuple(bshape...)
+ return tuple(bshape...)::typeof(sz)
 end
 
 # Check that all arguments are broadcast compatible with shape
@@ -180,7 +191,7 @@ function code_broadcasts(name::String, op)
  end
 
  function $fname(As::StridedArray...)
- $fname_T(promote_type([eltype(A) for A in As]...), As...)
+ $fname_T(Base.promote_eltype(As...), As...)
  end
 
  function $fname{T}(As::StridedArray{T}...)