Surprising error on example code from ModelingToolkit documentation!

I am having some issues with ModelingTookit.
I tried to run the example copy-paste code from the documentation. Component-Based Modeling a Spring-Mass System · ModelingToolkit.jl

using ModelingToolkit, Plots, DifferentialEquations, LinearAlgebra
using Symbolics: scalarize

@variables t
D = Differential(t)

function Mass(; name, m = 1.0, xy = [0., 0.], u = [0., 0.])
    ps = @parameters m=m
    sts = @variables pos[1:2](t)=xy v[1:2](t)=u
    eqs = scalarize(D.(pos) .~ v)
    ODESystem(eqs, t, [pos..., v...], ps; name)

function Spring(; name, k = 1e4, l = 1.)
    ps = @parameters k=k l=l
    @variables x(t), dir[1:2](t)
    ODESystem(Equation[], t, [x, dir...], ps; name)

function connect_spring(spring, a, b)
        spring.x ~ norm(scalarize(a .- b))
        scalarize(spring.dir .~ scalarize(a .- b))

spring_force(spring) = -spring.k .* scalarize(spring.dir) .* (spring.x - spring.l)  ./ spring.x

m = 1.0
xy = [1., -1.]
k = 1e4
l = 1.
center = [0., 0.]
g = [0., -9.81]
@named mass = Mass(m=m, xy=xy)
@named spring = Spring(k=k, l=l)

eqs = [
    connect_spring(spring, mass.pos, center)
    scalarize(D.(mass.v) .~ spring_force(spring) / mass.m .+ g)

@named _model = ODESystem(eqs, t)
@named model = compose(_model, mass, spring)
sys = structural_simplify(model)

prob = ODEProblem(sys, [], (0., 3.))
sol = solve(prob, Rosenbrock23())

I get the following error

ERROR: MethodError: no method matching AbstractFloat(::Type{Term{Float64, Nothing}})
Closest candidates are:
  (::Type{T})(::SymbolicUtils.Symbolic) where T<:Union{AbstractFloat, Integer, Complex{var"#s144"} where var"#s144"<:AbstractFloat, Complex{var"#s143"} where var"#s143"<:Integer} at /Users/adrianaperezrotondo/.julia/packages/Symbolics/hgePJ/src/Symbolics.jl:137
  (::Type{T})(::AbstractChar) where T<:Union{AbstractChar, Number} at char.jl:50
  (::Type{T})(::Base.TwicePrecision) where T<:Number at twiceprecision.jl:243
 [1] float(x::Type)
   @ Base ./float.jl:206
 [2] promote_to_concrete(vs::Vector{Term{Float64, Nothing}}; tofloat::Bool, use_union::Bool)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/utils.jl:480
 [3] varmap_to_vars(varmap::Vector{Any}, varlist::Vector{Term{Real, Base.ImmutableDict{DataType, Any}}}; defaults::Dict{Any, Any}, check::Bool, toterm::Function, promotetoconcrete::Nothing, tofloat::Bool, use_union::Bool)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/variables.jl:64
 [4] process_DEProblem(constructor::Type, sys::ODESystem, u0map::Vector{Any}, parammap::SciMLBase.NullParameters; implicit_dae::Bool, du0map::Nothing, version::Nothing, tgrad::Bool, jac::Bool, checkbounds::Bool, sparse::Bool, simplify::Bool, linenumbers::Bool, parallel::Symbolics.SerialForm, eval_expression::Bool, use_union::Bool, kwargs::Base.Iterators.Pairs{Symbol, Bool, Tuple{Symbol}, NamedTuple{(:has_difference,), Tuple{Bool}}})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/systems/diffeqs/abstractodesystem.jl:613
 [5] (ODEProblem{true, tType, isinplace, P, F, K, PT} where {tType, isinplace, P, F, K, PT})(sys::ODESystem, u0map::Vector{Any}, tspan::Tuple{Float64, Float64}, parammap::SciMLBase.NullParameters; callback::Nothing, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/systems/diffeqs/abstractodesystem.jl:704
 [6] (ODEProblem{true, tType, isinplace, P, F, K, PT} where {tType, isinplace, P, F, K, PT})(sys::ODESystem, u0map::Vector{Any}, tspan::Tuple{Float64, Float64}, parammap::SciMLBase.NullParameters) (repeats 2 times)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/systems/diffeqs/abstractodesystem.jl:703
 [7] ODEProblem(::ODESystem, ::Vector{Any}, ::Vararg{Any, N} where N; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/systems/diffeqs/abstractodesystem.jl:682
 [8] ODEProblem(::ODESystem, ::Vector{Any}, ::Vararg{Any, N} where N)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/gG7nj/src/systems/diffeqs/abstractodesystem.jl:682
 [9] top-level scope
   @ ~Code/Julia/CerebellarMotorLearning/scripts/ex.jl:48

I am using Julia-1.6 and Modelingtoolkit is up to date ModelingToolkit v8.11.0.
Please I would appreciate any help!

If you update to the latest versions this should hopefully fix everything I know recently MTK had breaking changes so could be that the documentation or you version of Julia is behind :slight_smile:

If there were breaking changes, wouldn’t this show up at the time of ]add ModelingToolkit? (Assuming MTK’s compat file is correctly annotated.)