Error with StaticArray of non-isbitstype's

[marius311]

This was discussed in #547 (comment) but just wanted to make this issue to track it and to provide a MWE (StaticArrays 0.12.3 / Zygote 0.4.20):

julia> using StaticArrays, Zygote

julia> x = @SVector[ [1,2] ]
1-element SArray{Tuple{1},Array{Int64,1},1,1} with indices SOneTo(1):
 [1, 2]

julia> gradient(x -> sum(x[1]), x)
ERROR: setindex!() with non-isbitstype eltype is not supported by StaticArrays. Consider using SizedArray.
Stacktrace:
 [1] error(::String) at ./error.jl:33
 [2] setindex! at /home/marius/.julia/packages/StaticArrays/mlIi1/src/MArray.jl:99 [inlined]
 [3] macro expansion at /home/marius/.julia/packages/StaticArrays/mlIi1/src/arraymath.jl:105 [inlined]
 [4] _fill! at /home/marius/.julia/packages/StaticArrays/mlIi1/src/arraymath.jl:101 [inlined]
 [5] fill!(::MArray{Tuple{1},Union{Nothing, FillArrays.Fill{Int64,1,Tuple{Base.OneTo{Int64}}}},1,1}, ::Nothing) at /home/marius/.julia/packages/StaticArrays/mlIi1/src/arraymath.jl:99
 [6] _zero(::SArray{Tuple{1},Array{Int64,1},1,1}, ::Type{T} where T) at /home/marius/.julia/packages/Zygote/YeCEW/src/lib/array.jl:52
 [7] (::Zygote.var"#1040#1042"{SArray{Tuple{1},Array{Int64,1},1,1},Tuple{Int64}})(::FillArrays.Fill{Int64,1,Tuple{Base.OneTo{Int64}}}) at /home/marius/.julia/packages/Zygote/YeCEW/src/lib/array.jl:40
 [8] (::Zygote.var"#2739#back#1036"{Zygote.var"#1040#1042"{SArray{Tuple{1},Array{Int64,1},1,1},Tuple{Int64}}})(::FillArrays.Fill{Int64,1,Tuple{Base.OneTo{Int64}}}) at /home/marius/.julia/packages/ZygoteRules/6nssF/src/adjoint.jl:49
 [9] literal_getindex at /home/marius/.julia/packages/Zygote/YeCEW/src/lib/lib.jl:94 [inlined]
 [10] (::typeof(∂(literal_getindex)))(::FillArrays.Fill{Int64,1,Tuple{Base.OneTo{Int64}}}) at /home/marius/.julia/packages/Zygote/YeCEW/src/compiler/interface2.jl:0
 [11] #13 at ./none:1 [inlined]
 [12] (::typeof(∂(#13)))(::Int64) at /home/marius/.julia/packages/Zygote/YeCEW/src/compiler/interface2.jl:0
 [13] (::Zygote.var"#36#37"{typeof(∂(#13))})(::Int64) at /home/marius/.julia/packages/Zygote/YeCEW/src/compiler/interface.jl:46
 [14] gradient(::Function, ::SArray{Tuple{1},Array{Int64,1},1,1}) at /home/marius/.julia/packages/Zygote/YeCEW/src/compiler/interface.jl:55
 [15] top-level scope at none:0

I actually think the fix belongs in StaticArrays: JuliaArrays/StaticArrays.jl#799

[adienes]

should be fixed now in https://github.com/JuliaArrays/StaticArrays.jl/releases/tag/v1.6.4 ?