UndefVarError: `ct` not defined

[ForceBru]

The version of Libtask that's currently shipped with Turing.jl (0.5.1, I guess) raises this error when I run sample(model, sampler, 100):

CTaskException:
Failed to show error:
UndefVarError: ct not defined
Stacktrace:
[1] showerror(io::IOBuffer, ex::Libtask.CTaskException)
@ Libtask ~/.julia/packages/Libtask/00Il9/src/ctask.jl:30
[2] try_showerror(::IOBuffer, ::Libtask.CTaskException)
@ Main.PlutoRunner ~/.julia/packages/Pluto/yDJcG/src/runner/PlutoRunner.jl:454
[3] sprint(f::Function, args::Libtask.CTaskException; context::Nothing, sizehint::Int64)
@ Base ./strings/io.jl:105
[4] sprint(f::Function, args::Libtask.CTaskException)
@ Base ./strings/io.jl:101
[5] format_output(val::CapturedException; context::Pair{Symbol, Dict{Tuple{UInt64, Int64}, Int64}})
@ Main.PlutoRunner ~/.julia/packages/Pluto/yDJcG/src/runner/PlutoRunner.jl:549
[6] formatted_result_of(cell_id::Base.UUID, ends_with_semicolon::Bool, showmore::Nothing)
@ Main.PlutoRunner ~/.julia/packages/Pluto/yDJcG/src/runner/PlutoRunner.jl:436
[7] top-level scope
@ none:1
[8] eval(m::Module, e::Any)
@ Core ./boot.jl:360
[9] (::Distributed.var"#106#108"{Distributed.CallMsg{:call_fetch}})()
@ Distributed /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:278
[10] run_work_thunk(thunk::Distributed.var"#106#108"{Distributed.CallMsg{:call_fetch}}, print_error::Bool)
@ Distributed /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:63
[11] macro expansion
@ /Users/julia/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:278 [inlined]
[12] (::Distributed.var"#105#107"{Distributed.CallMsg{:call_fetch}, Distributed.MsgHeader, Sockets.TCPSocket})()
@ Distributed ./task.jl:411

This happens because, indeed, ct is not defined in version 0.5.1:

Libtask.jl/src/ctask.jl

Lines 25 to 33 in ca8099f

	function Base.showerror(io::IO, ex::CTaskException)
	println(io, "CTaskException:")
	bt = @static if VERSION < v"1.6.0-DEV.1145"
	ct.backtrace
	else
	ct.storage[:_libtask_bt]
	end
	showerror(io, ex.task.exception, bt)
	end

It was fixed in the next commit:

Libtask.jl/src/ctask.jl

Lines 30 to 35 in c66b8c9

	ct = ex.task
	bt = @static if VERSION < v"1.6.0-DEV.1145"
	ct.backtrace
	else
	ct.storage[:_libtask_bt]
	end

...yet this version was never published, it seems? Turing v0.15.20 uses Libtask 0.5.1:

[[Libtask]]
deps = ["Libtask_jll", "LinearAlgebra", "Statistics"]
git-tree-sha1 = "6088b80fb5017440579ea8113a516ad2807afe19"
uuid = "6f1fad26-d15e-5dc8-ae53-837a1d7b8c9f"
version = "0.5.1"

[[Libtask_jll]]
deps = ["Artifacts", "JLLWrappers", "Libdl", "Pkg"]
git-tree-sha1 = "901fc8752bbc527a6006a951716d661baa9d54e9"
uuid = "3ae2931a-708c-5973-9c38-ccf7496fb450"
version = "0.4.3+0"

---

• julia version 1.6.1
• Turing.jl version 0.15.20
• macOS

[ForceBru]

An example:

using Turing, Distributions

@model function GMM(x::AbstractVector, n_components::Integer, ::Type{U}=Unsigned, ::Type{F}=Float64) where {U <: Unsigned, F <: Real}
    N = length(x)
    W ~ Dirichlet(ones(n_components))
    
    Z ~ filldist(Categorical(W), N)
    μs ~ filldist(Normal(0, 10), n_components)
    σs ~ filldist(Uniform(0, 1), n_components)
    
    for t ∈ 1:N
        x[t] ~ Normal(μs[Z[t]], σs[Z[t]])
    end
    
    x, Z, W, μs, σs
end

model = GMM(fill(missing, 500), 4)

ret = sample(model, Gibbs(HMC(0.01, 10, :W, :μs, :σs), PG(50, :Z)), 20)

@show ret

This produces the error and crashes Julia:

~/test $ julia turing_bug.jl                                             (base) 
Sampling 100%|██████████████████████████████████████████| Time: 0:00:19
ERROR: LoadError: CTaskException:

Stacktrace:
  [1] consume(::CTask)
    @ Libtask ~/.julia/packages/Libtask/00Il9/src/ctask.jl:210
  [2] advance!(trace::AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}})
    @ Turing.Core ~/.julia/packages/Turing/TbEZL/src/core/container.jl:26
  [3] reweight!(pc::AdvancedPS.ParticleContainer{AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}}})
    @ AdvancedPS ~/.julia/packages/AdvancedPS/kYdfv/src/container.jl:273
  [4] sweep!(rng::Random._GLOBAL_RNG, pc::AdvancedPS.ParticleContainer{AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}}}, resampler::AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64})
    @ AdvancedPS ~/.julia/packages/AdvancedPS/kYdfv/src/container.jl:327
  [5] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/AdvancedSMC.jl:261
  [6] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/AdvancedSMC.jl:250
  [7] (::Turing.Inference.var"#90#92"{Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Random._GLOBAL_RNG, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}})(local_spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:204
  [8] map
    @ ./tuple.jl:214 [inlined]
  [9] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:197
 [10] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:167
 [11] step(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}; resume_from::Nothing, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ DynamicPPL ~/.julia/packages/DynamicPPL/wCsuo/src/sampler.jl:87
 [12] step
    @ ~/.julia/packages/DynamicPPL/wCsuo/src/sampler.jl:62 [inlined]
 [13] macro expansion
    @ ~/.julia/packages/AbstractMCMC/ByHEr/src/sample.jl:123 [inlined]
 [14] macro expansion
    @ ~/.julia/packages/ProgressLogging/6KXlp/src/ProgressLogging.jl:328 [inlined]
 [15] (::AbstractMCMC.var"#21#22"{Bool, String, Nothing, Int64, Int64, Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Random._GLOBAL_RNG, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, Int64, Int64})()
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:11
 [16] with_logstate(f::Function, logstate::Any)
    @ Base.CoreLogging ./logging.jl:491
 [17] with_logger(f::Function, logger::LoggingExtras.TeeLogger{Tuple{LoggingExtras.EarlyFilteredLogger{TerminalLoggers.TerminalLogger, AbstractMCMC.var"#1#3"{Module}}, LoggingExtras.EarlyFilteredLogger{Logging.ConsoleLogger, AbstractMCMC.var"#2#4"{Module}}}})
    @ Base.CoreLogging ./logging.jl:603
 [18] with_progresslogger(f::Function, _module::Module, logger::Logging.ConsoleLogger)
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:34
 [19] macro expansion
    @ ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:10 [inlined]
 [20] mcmcsample(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, sampler::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, N::Int64; progress::Bool, progressname::String, callback::Nothing, discard_initial::Int64, thinning::Int64, chain_type::Type, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/sample.jl:114
 [21] sample(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, sampler::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, N::Int64; chain_type::Type, resume_from::Nothing, progress::Bool, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:156
 [22] sample
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:155 [inlined]
 [23] #sample#2
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:142 [inlined]
 [24] sample
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:142 [inlined]
 [25] #sample#1
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:132 [inlined]
 [26] sample(model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, alg::Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}, N::Int64)
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:132
 [27] top-level scope
    @ ~/test/turing_bug.jl:20ERROR: UndefVarError: ct not defined
Stacktrace:
  [1] showerror(io::IOContext{Base.TTY}, ex::Libtask.CTaskException)
    @ Libtask ~/.julia/packages/Libtask/00Il9/src/ctask.jl:30
  [2] showerror(io::IOContext{Base.TTY}, ex::Libtask.CTaskException, bt::Vector{Base.StackTraces.StackFrame}; backtrace::Bool)
    @ Base ./errorshow.jl:88
  [3] showerror(io::IOContext{Base.TTY}, ex::LoadError, bt::Vector{Base.StackTraces.StackFrame}; backtrace::Bool)
    @ Base ./errorshow.jl:96
  [4] show_exception_stack(io::IOContext{Base.TTY}, stack::Vector{Any})
    @ Base ./errorshow.jl:877
  [5] display_error(io::Base.TTY, stack::Vector{Any})
    @ Base ./client.jl:104
  [6] display_error(stack::Vector{Any})
    @ Base ./client.jl:107
  [7] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
  [8] invokelatest
    @ ./essentials.jl:706 [inlined]
  [9] exec_options(opts::Base.JLOptions)
    @ Base ./client.jl:287
 [10] _start()
    @ Base ./client.jl:485

caused by: LoadError: CTaskException:

Stacktrace:
  [1] consume(::CTask)
    @ Libtask ~/.julia/packages/Libtask/00Il9/src/ctask.jl:210
  [2] advance!(trace::AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}})
    @ Turing.Core ~/.julia/packages/Turing/TbEZL/src/core/container.jl:26
  [3] reweight!(pc::AdvancedPS.ParticleContainer{AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}}})
    @ AdvancedPS ~/.julia/packages/AdvancedPS/kYdfv/src/container.jl:273
  [4] sweep!(rng::Random._GLOBAL_RNG, pc::AdvancedPS.ParticleContainer{AdvancedPS.Trace{Turing.Core.TracedModel{DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}}}}, resampler::AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64})
    @ AdvancedPS ~/.julia/packages/AdvancedPS/kYdfv/src/container.jl:327
  [5] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/AdvancedSMC.jl:261
  [6] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/AdvancedSMC.jl:250
  [7] (::Turing.Inference.var"#90#92"{Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Random._GLOBAL_RNG, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}})(local_spl::DynamicPPL.Sampler{PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:204
  [8] map
    @ ./tuple.jl:214 [inlined]
  [9] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64}; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:197
 [10] initialstep(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, vi::DynamicPPL.TypedVarInfo{NamedTuple{(:W, :Z, :μs, :σs, :x), Tuple{DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:W, Tuple{}}, Int64}, Vector{Dirichlet{Float64, Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:W, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:Z, Tuple{}}, Int64}, Vector{Product{Discrete, Categorical{Float64, Vector{Float64}}, FillArrays.Fill{Categorical{Float64, Vector{Float64}}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:Z, Tuple{}}}, Vector{Int64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:μs, Tuple{}}, Int64}, Vector{DistributionsAD.TuringScalMvNormal{Vector{Float64}, Float64}}, Vector{AbstractPPL.VarName{:μs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:σs, Tuple{}}, Int64}, Vector{Product{Continuous, Uniform{Float64}, FillArrays.Fill{Uniform{Float64}, 1, Tuple{Base.OneTo{Int64}}}}}, Vector{AbstractPPL.VarName{:σs, Tuple{}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}, DynamicPPL.Metadata{Dict{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}, Int64}, Vector{Normal{Float64}}, Vector{AbstractPPL.VarName{:x, Tuple{Tuple{Int64}}}}, Vector{Float64}, Vector{Set{DynamicPPL.Selector}}}}}, Float64})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/gibbs.jl:167
 [11] step(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, spl::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}; resume_from::Nothing, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ DynamicPPL ~/.julia/packages/DynamicPPL/wCsuo/src/sampler.jl:87
 [12] step
    @ ~/.julia/packages/DynamicPPL/wCsuo/src/sampler.jl:62 [inlined]
 [13] macro expansion
    @ ~/.julia/packages/AbstractMCMC/ByHEr/src/sample.jl:123 [inlined]
 [14] macro expansion
    @ ~/.julia/packages/ProgressLogging/6KXlp/src/ProgressLogging.jl:328 [inlined]
 [15] (::AbstractMCMC.var"#21#22"{Bool, String, Nothing, Int64, Int64, Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Random._GLOBAL_RNG, DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, Int64, Int64})()
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:11
 [16] with_logstate(f::Function, logstate::Any)
    @ Base.CoreLogging ./logging.jl:491
 [17] with_logger(f::Function, logger::LoggingExtras.TeeLogger{Tuple{LoggingExtras.EarlyFilteredLogger{TerminalLoggers.TerminalLogger, AbstractMCMC.var"#1#3"{Module}}, LoggingExtras.EarlyFilteredLogger{Logging.ConsoleLogger, AbstractMCMC.var"#2#4"{Module}}}})
    @ Base.CoreLogging ./logging.jl:603
 [18] with_progresslogger(f::Function, _module::Module, logger::Logging.ConsoleLogger)
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:34
 [19] macro expansion
    @ ~/.julia/packages/AbstractMCMC/ByHEr/src/logging.jl:10 [inlined]
 [20] mcmcsample(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, sampler::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, N::Int64; progress::Bool, progressname::String, callback::Nothing, discard_initial::Int64, thinning::Int64, chain_type::Type, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ AbstractMCMC ~/.julia/packages/AbstractMCMC/ByHEr/src/sample.jl:114
 [21] sample(rng::Random._GLOBAL_RNG, model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, sampler::DynamicPPL.Sampler{Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}}, N::Int64; chain_type::Type, resume_from::Nothing, progress::Bool, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:156
 [22] sample
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:155 [inlined]
 [23] #sample#2
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:142 [inlined]
 [24] sample
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:142 [inlined]
 [25] #sample#1
    @ ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:132 [inlined]
 [26] sample(model::DynamicPPL.Model{var"#1#2", (:x, :n_components, :U, :F), (:U, :F), (), Tuple{Vector{Missing}, Int64, Type{Unsigned}, Type{Float64}}, Tuple{Type{Unsigned}, Type{Float64}}}, alg::Gibbs{(:W, :μs, :σs, :Z), Tuple{HMC{Turing.Core.ForwardDiffAD{40}, (:W, :μs, :σs), AdvancedHMC.UnitEuclideanMetric}, PG{(:Z,), AdvancedPS.ResampleWithESSThreshold{typeof(AdvancedPS.resample_systematic), Float64}}}}, N::Int64)
    @ Turing.Inference ~/.julia/packages/Turing/TbEZL/src/inference/Inference.jl:132
 [27] top-level scope
    @ ~/test/turing_bug.jl:20fatal: error thrown and no exception handler available.
UndefVarError(var=:ct)
jl_undefined_var_error at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
jl_get_binding_or_error at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
showerror at /Users/forcebru/.julia/packages/Libtask/00Il9/src/ctask.jl:30
#showerror#760 at ./errorshow.jl:88
showerror##kw at ./errorshow.jl:87
unknown function (ip: 0x1487152f5)
jl_apply_generic at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
#showerror#761 at ./errorshow.jl:96
showerror##kw at ./errorshow.jl:95
unknown function (ip: 0x14870e455)
jl_apply_generic at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
show_exception_stack at ./errorshow.jl:877
display_error at ./client.jl:104
jl_apply_generic at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
display_error at ./client.jl:107
jl_apply_generic at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
jl_f__call_latest at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
#invokelatest#2 at ./essentials.jl:708 [inlined]
invokelatest at ./essentials.jl:706 [inlined]
_start at ./client.jl:487
jfptr__start_32022.clone_1 at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_apply_generic at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
true_main at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
repl_entrypoint at /Applications/Julia-1.6.app/Contents/Resources/julia/lib/julia/libjulia-internal.1.6.dylib (unknown line)
~/test [1] $

[devmotion]

The error "ct not defined" is fixed in Libtask 0.5.2 and the example does not crash Julia anymore.