Update to the latest broadcast implement.

src/structarray.jl

@@ -497,33 +497,53 @@
 import Base.Broadcast: BroadcastStyle, AbstractArrayStyle, Broadcasted, DefaultArrayStyle, Unknown, ArrayConflict
 using Base.Broadcast: combine_styles
 
-struct StructArrayStyle{S, N} <: AbstractArrayStyle{N} end
+@static if fieldcount(Base.Broadcast.Broadcasted) == 4
+    struct StructArrayStyle{N, S} <: AbstractArrayStyle{N}
+        style::S
+        StructArrayStyle{N}(style) where {N} = new{N, typeof(style)}(style)
+    end
+    StructArrayStyle{N}(style::StructArrayStyle) where {N} = StructArrayStyle{N}(style.style)
+    parent_style(s::BroadcastStyle) = s
+    parent_style(s::StructArrayStyle) = s.style
+    style(bc::Broadcasted) = bc.style
+    const broadcasted = Broadcasted
+else
+    struct StructArrayStyle{N, S} <: AbstractArrayStyle{N}
+        StructArrayStyle{N}(style) where {N} = new{N, typeof(style)}()
+    end
+    StructArrayStyle{N}(style::StructArrayStyle{M, S}) where {N, M, S} = StructArrayStyle{N}(S())
+    parent_style(s::BroadcastStyle) = s
+    parent_style(::StructArrayStyle{N, S}) where {N, S} = S()
+    style(::Broadcasted{Style}) where {Style} = Style()
+    broadcasted(s, f, args, axes) = Broadcasted{typeof(s)}(f, args, axes)
+end
+StructArrayStyle{N, S}() where {N, S} = StructArrayStyle{N}(S())
+parent_style(bc::Broadcasted) = parent_style(style(bc))
+ofstyle(s, bc::Broadcasted) = broadcasted(s, bc.f, bc.args, bc.axes)
 
 # Here we define the dimension tracking behavior of StructArrayStyle
-function StructArrayStyle{S, M}(::Val{N}) where {S, M, N}
+function StructArrayStyle{M, S}(::Val{N}) where {S, M, N}
     T = S <: AbstractArrayStyle{M} ? typeof(S(Val{N}())) : S
-    return StructArrayStyle{T, N}()
+    return StructArrayStyle{N, T}()
 end
 
 # StructArrayStyle is a wrapped style.
 # Here we try our best to resolve style conflict.
-function BroadcastStyle(b::AbstractArrayStyle{M}, a::StructArrayStyle{S, N}) where {S, N, M}
+function BroadcastStyle(b::AbstractArrayStyle{M}, a::StructArrayStyle{N, S}) where {S, N, M}
     N′ = M === Any || N === Any ? Any : max(M, N)
-    S′ = Broadcast.result_style(S(), b)
-    return S′ isa StructArrayStyle ? typeof(S′)(Val{N′}()) : StructArrayStyle{typeof(S′), N′}()
+    return StructArrayStyle{N′}(Broadcast.result_style(parent_style(a), b))
 end
 BroadcastStyle(::StructArrayStyle, ::DefaultArrayStyle) = Unknown()
 
 @inline combine_style_types(::Type{A}, args...) where {A<:AbstractArray} =
     combine_style_types(BroadcastStyle(A), args...)
 @inline combine_style_types(s::BroadcastStyle, ::Type{A}, args...) where {A<:AbstractArray} =
     combine_style_types(Broadcast.result_style(s, BroadcastStyle(A)), args...)
-combine_style_types(::StructArrayStyle{S}) where {S} = S() # avoid nested StructArrayStyle
 combine_style_types(s::BroadcastStyle) = s
 
 Base.@pure cst(::Type{SA}) where {SA} = combine_style_types(array_types(SA).parameters...)
 
-BroadcastStyle(::Type{SA}) where {SA<:StructArray} = StructArrayStyle{typeof(cst(SA)), ndims(SA)}()
+BroadcastStyle(::Type{SA}) where {SA<:StructArray} = StructArrayStyle{ndims(SA)}(cst(SA))
 
 """
     always_struct_broadcast(style::BroadcastStyle)
@@ -551,8 +571,8 @@
 """
 try_struct_copy(bc::Broadcasted) = copy(bc)
 
-function Base.copy(bc::Broadcasted{StructArrayStyle{S, N}}) where {S, N}
-    if always_struct_broadcast(S())
+function Base.copy(bc::Broadcasted{<:StructArrayStyle})
+    if always_struct_broadcast(parent_style(bc))
         return invoke(copy, Tuple{Broadcasted}, bc)
     else
         return try_struct_copy(replace_structarray(bc))
@@ -567,55 +587,49 @@
 supports `AbstractArray`. But some `BroadcastStyle` limits the input array types, 
 e.g. `StaticArrayStyle`, thus we have to omit all `StructArray`.
 """
-function replace_structarray(bc::Broadcasted{Style}) where {Style}
+function replace_structarray(bc::Broadcasted)
     args = replace_structarray_args(bc.args)
-    Style′ = parent_style(Style())
-    return Broadcasted{Style′}(bc.f, args, bc.axes)
+    style = parent_style(bc)
+    return broadcasted(style, bc.f, args, bc.axes)
 end
 function replace_structarray(A::StructArray)
     f = Instantiator(eltype(A))
     args = Tuple(components(A))
-    Style = typeof(combine_styles(args...))
-    return Broadcasted{Style}(f, args, axes(A))
+    style = combine_styles(args...)
+    return broadcasted(style, f, args, axes(A))
 end
 replace_structarray(@nospecialize(A)) = A
 
 replace_structarray_args(args::Tuple) = (replace_structarray(args[1]), replace_structarray_args(tail(args))...)
 replace_structarray_args(::Tuple{}) = ()
 
-parent_style(@nospecialize(x)) = typeof(x)
-parent_style(::StructArrayStyle{S, N}) where {S, N} = S
-parent_style(::StructArrayStyle{S, N}) where {N, S<:AbstractArrayStyle{N}} = S
-parent_style(::StructArrayStyle{S, N}) where {S<:AbstractArrayStyle{Any}, N} = S
-parent_style(::StructArrayStyle{S, N}) where {S<:AbstractArrayStyle, N} = typeof(S(Val(N)))
-
 # `instantiate` and `_axes` might be overloaded for static axes.
-function Broadcast.instantiate(bc::Broadcasted{Style}) where {Style <: StructArrayStyle}
-    Style′ = parent_style(Style())
-    bc′ = Broadcast.instantiate(convert(Broadcasted{Style′}, bc))
-    return convert(Broadcasted{Style}, bc′)
+function Broadcast.instantiate(bc::Broadcasted{<:StructArrayStyle})
+    bc′ = Broadcast.instantiate(ofstyle(parent_style(bc), bc))
+    return ofstyle(style(bc), bc′)
 end
 
-function Broadcast._axes(bc::Broadcasted{Style}, ::Nothing) where {Style <: StructArrayStyle}
-    Style′ = parent_style(Style())
-    return Broadcast._axes(convert(Broadcasted{Style′}, bc), nothing)
+function Broadcast._axes(bc::Broadcasted{<:StructArrayStyle}, ::Nothing)
+    return Broadcast._axes(ofstyle(parent_style(bc), bc), nothing)
 end
 
 # Here we use `similar` defined for `S` to build the dest Array.
-function Base.similar(bc::Broadcasted{StructArrayStyle{S, N}}, ::Type{ElType}) where {S, N, ElType}
-    bc′ = convert(Broadcasted{S}, bc)
+function Base.similar(bc::Broadcasted{<:StructArrayStyle}, ::Type{ElType}) where {ElType}
+    bc′ = ofstyle(parent_style(bc), bc)
     return isnonemptystructtype(ElType) ? buildfromschema(T -> similar(bc′, T), ElType) : similar(bc′, ElType)
 end
 
 # Unwrapper to recover the behaviour defined by parent style.
-@inline function Base.copyto!(dest::AbstractArray, bc::Broadcasted{StructArrayStyle{S, N}}) where {S, N}
-    bc′ = always_struct_broadcast(S()) ? convert(Broadcasted{S}, bc) : replace_structarray(bc)
+@inline function Base.copyto!(dest::AbstractArray, bc::Broadcasted{<:StructArrayStyle})
+    ps = parent_style(bc)
+    bc′ = always_struct_broadcast(ps) ? ofstyle(ps, bc) : replace_structarray(bc)
     return copyto!(dest, bc′)
 end
 
-@inline function Broadcast.materialize!(::StructArrayStyle{S}, dest, bc::Broadcasted) where {S}
-    bc′ = always_struct_broadcast(S()) ? bc : replace_structarray(bc)
-    return Broadcast.materialize!(S(), dest, bc′)
+@inline function Broadcast.materialize!(s::StructArrayStyle, dest, bc::Broadcasted)
+    ps = parent_style(s)
+    bc′ = always_struct_broadcast(ps) ? bc : replace_structarray(bc)
+    return Broadcast.materialize!(ps, dest, bc′)
 end
 
 # for aliasing analysis during broadcast

test/runtests.jl

@@ -1227,7 +1227,7 @@ Base.BroadcastStyle(::Broadcast.ArrayStyle{MyArray2}, S::Broadcast.DefaultArrayS
             ares = map(a->a.re, as)
             aims = map(a->a.im, as)
             style = Broadcast.combine_styles(ares...)
-            @test Broadcast.combine_styles(as...) === StructArrayStyle{typeof(style),1}()
+            @test Broadcast.combine_styles(as...) === StructArrayStyle{1,typeof(style)}()
             if !(style in tested_style)
                 push!(tested_style, style)
                 if style isa Broadcast.ArrayStyle{MyArray3}
@@ -1249,8 +1249,8 @@ Base.BroadcastStyle(::Broadcast.ArrayStyle{MyArray2}, S::Broadcast.DefaultArrayS
     @test Base.broadcasted(+, s, MyArray1(rand(2))) isa Broadcast.Broadcasted{<:Broadcast.AbstractArrayStyle{Any}}
 
     #parent_style
-    @test StructArrays.parent_style(StructArrayStyle{Broadcast.DefaultArrayStyle{0},2}()) == Broadcast.DefaultArrayStyle{2}
-    @test StructArrays.parent_style(StructArrayStyle{Broadcast.Style{Tuple},2}()) == Broadcast.Style{Tuple}
+    @test StructArrays.parent_style(StructArrayStyle{2,Broadcast.DefaultArrayStyle{0}}()) == Broadcast.DefaultArrayStyle{0}()
+    @test StructArrays.parent_style(StructArrayStyle{2,Broadcast.Style{Tuple}}()) == Broadcast.Style{Tuple}()
 
     # allocation test for overloaded `broadcast_unalias`
     StructArrays.always_struct_broadcast(::Broadcast.ArrayStyle{MyArray1}) = false