Support Zeros(5)./Zeros(5) (#116) (#117)

Author: dlfivefifty

src/fillbroadcast.jl

@@ -30,6 +30,7 @@ end
 
 _broadcasted_zeros(f, a, b) = Zeros{Base.Broadcast.combine_eltypes(f, (a, b))}(broadcast_shape(axes(a), axes(b)))
 _broadcasted_ones(f, a, b) = Ones{Base.Broadcast.combine_eltypes(f, (a, b))}(broadcast_shape(axes(a), axes(b)))
+_broadcasted_nan(f, a, b) = Fill(convert(Base.Broadcast.combine_eltypes(f, (a, b)), NaN), broadcast_shape(axes(a), axes(b)))
 
 # TODO: remove at next breaking version
 _broadcasted_zeros(a, b) = _broadcasted_zeros(+, a, b)
@@ -75,6 +76,10 @@ for op in (:*, :/, :\)
     @eval broadcasted(::DefaultArrayStyle, ::typeof($op), a::Ones, b::Ones) = _broadcasted_ones($op, a, b)
 end
 
+for op in (:/, :\)
+    @eval broadcasted(::DefaultArrayStyle, ::typeof($op), a::Zeros{<:Number}, b::Zeros{<:Number}) = _broadcasted_nan($op, a, b)
+end
+
 # special case due to missing converts for ranges
 _range_convert(::Type{AbstractVector{T}}, a::AbstractRange{T}) where T = a
 _range_convert(::Type{AbstractVector{T}}, a::AbstractUnitRange) where T = convert(T,first(a)):convert(T,last(a))

test/runtests.jl

@@ -591,6 +591,11 @@ end
             @test broadcast(*, Fill([1,2],3), Zeros(3)) isa Fill{Vector{Float64}}
             @test broadcast(*, [[1,2], [3,4,5]], Zeros(2)) == broadcast(*, Zeros(2), [[1,2], [3,4,5]]) == broadcast(*, zeros(2), [[1,2], [3,4,5]])
         end
+
+        @testset "NaN" begin
+            @test Zeros(5) ./ Zeros(5) ≡ Zeros(5) .\ Zeros(5) ≡ Fill(NaN,5)
+            @test Zeros{Int}(5,6) ./ Zeros{Int}(5) ≡ Zeros{Int}(5) .\ Zeros{Int}(5,6) ≡ Fill(NaN,5,6)
+        end
     end
 
     @testset "support Ref" begin