further simplify

Author: ChrisRackauckas

ext/RecursiveArrayToolsZygoteExt.jl

@@ -4,12 +4,15 @@ using RecursiveArrayTools
 
 if isdefined(Base, :get_extension)
     using Zygote
-    using Zygote: FillArrays, literal_getproperty, @adjoint
+    using Zygote: FillArrays, ChainRulesCore, literal_getproperty, @adjoint
 else
     using ..Zygote
-    using ..Zygote: FillArrays, literal_getproperty, @adjoint
+    using ..Zygote: FillArrays, ChainRulesCore, literal_getproperty, @adjoint
 end
 
+# Define a new species of projection operator for this type:
+ChainRulesCore.ProjectTo(x::VectorOfArray) = ChainRulesCore.ProjectTo{VectorOfArray}()
+
 @adjoint function getindex(VA::AbstractVectorOfArray, i::Int)
     function AbstractVectorOfArray_getindex_adjoint(Δ)
         Δ′ = [(i == j ? Δ : Fill(zero(eltype(x)), size(x)))

src/RecursiveArrayTools.jl

@@ -20,7 +20,6 @@ include("utils.jl")
 include("vector_of_array.jl")
 include("tabletraits.jl")
 include("array_partition.jl")
-include("zygote.jl")
 
 function Base.show(io::IO, x::Union{ArrayPartition, AbstractVectorOfArray})
     invoke(show, Tuple{typeof(io), Any}, io, x)