fix nested structarrays broadcasting (#249)

Author: aplavin

src/structarray.jl

@@ -505,7 +505,7 @@ Base.@pure cst(::Type{SA}) where {SA} = combine_style_types(array_types(SA).para
 
 BroadcastStyle(::Type{SA}) where {SA<:StructArray} = StructArrayStyle{typeof(cst(SA)), ndims(SA)}()
 
-function Base.similar(bc::Broadcasted{StructArrayStyle{S, N}}, ::Type{ElType}) where {S<:DefaultArrayStyle, N, ElType}
+function Base.similar(bc::Broadcasted{StructArrayStyle{S, N}}, ::Type{ElType}) where {S<:Union{DefaultArrayStyle,StructArrayStyle}, N, ElType}
     ContainerType = isnonemptystructtype(ElType) ? StructArray{ElType} : Array{ElType}
     return similar(ContainerType, axes(bc))
 end

test/runtests.jl

@@ -1142,6 +1142,9 @@ Base.similar(bc::Broadcast.Broadcasted{Broadcast.ArrayStyle{MyArray}}, ::Type{El
     # issue #189
     v = StructArray([(a="s1",), (a="s2",)])
     @test @inferred(broadcast(el -> el.a, v)) == ["s1", "s2"]
+
+    @test identity.(StructArray(x=StructArray(a=1:3)))::StructArray == [(x=(a=1,),), (x=(a=2,),), (x=(a=3,),)]
+    @test (x -> x.x.a).(StructArray(x=StructArray(a=1:3))) == [1, 2, 3]
 end
 
 @testset "map" begin