TypedVarInfo failing for certain models over empty vectors

[phipsgabler]

What's happening here?

julia> @model function test_empty(n)
           b = Beta(2, 2)
           x ~ product_distribution(Fill(b, n))
           y ~ MvNormal(x, ones(n))
       end
test_empty (generic function with 2 methods)

julia> VarInfo(test_empty(0))
ERROR: MethodError: no method matching DynamicPPL.Metadata(::Dict{VarName{:x, Setfield.IdentityLens}, Int64}, ::Vector{VarName{:x, Setfield.IdentityLens}}, ::Vector{UnitRange{Int64}}, ::Vector{Any}, ::Vector{Product{Continuous, Beta{Float64}, Fill{Beta{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, ::Vector{Set{DynamicPPL.Selector}}, ::Vector{Int64}, ::Dict{String, BitVector})
Closest candidates are:
  DynamicPPL.Metadata(::TIdcs, ::TVN, ::Vector{UnitRange{Int64}}, ::TVal, ::TDists, ::TGIds, ::Vector{Int64}, ::Dict{String, BitVector}) where {TIdcs<:(Dict{<:VarName, Int64}), TDists<:(AbstractVector{<:Distribution}), TVN<:(AbstractVector{<:VarName}), TVal<:(AbstractVector{<:Real}), TGIds<:AbstractVector{Set{DynamicPPL.Selector}}} at ~/.julia/packages/DynamicPPL/zPOYL/src/varinfo.jl:47
Stacktrace:
 [1] (TypedVarInfo)(vi::UntypedVarInfo{DynamicPPL.Metadata{Dict{VarName, Int64}, Vector{Distribution}, Vector{VarName}, Vector{Real}, Vector{Set{DynamicPPL.Selector}}}, Float64})
   @ DynamicPPL ~/.julia/packages/DynamicPPL/zPOYL/src/varinfo.jl:588
 [2] VarInfo
   @ ~/.julia/packages/DynamicPPL/zPOYL/src/varinfo.jl:128 [inlined]
 [3] VarInfo
   @ ~/.julia/packages/DynamicPPL/zPOYL/src/varinfo.jl:126 [inlined]
 [4] VarInfo(::Model{typeof(test_empty), (:n,), (), (), Tuple{Int64}, Tuple{}, DefaultContext})
   @ DynamicPPL ~/.julia/packages/DynamicPPL/zPOYL/src/varinfo.jl:130
 [5] top-level scope
   @ REPL[94]:1

Is it because this line is an empty comprehension and resulting in a Vector{Any}?

[phipsgabler]

Haha! Yes!

vi = VarInfo(); test_empty(0)(vi);

julia> [copy.(vi.metadata.vals[i]) for i in 1:0]
Any[]

julia> [vi.metadata.vals[i] for i in 1:0]
Any[]

julia> vi = VarInfo(); test_empty(1)(vi);

julia> [copy.(vi.metadata.vals[i]) for i in 1:0]
Any[]

julia> [copy.(vi.metadata.vals[i]) for i in (1:1, 2:2)]
2-element Vector{Vector{Float64}}:
 [0.2861633416006399]
 [-0.5199045701696932]

julia> [vi.metadata.vals[i] for i in (1:1, 2:2)]
2-element Vector{Vector{Real}}:
 [0.2861633416006399]
 [-0.5199045701696932]