Issue with scoping rules of parameter (and variable) declaration in components (Catalyst vs ModelingToolkit)

Specific Domains Modelling & Simulations
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4

Thanks a lot for your answer!
Following your suggestion, if add a reaction to the reaction system, the problem arises:

n1 = @network_component n1 begin
    @parameters k = 1.0
    @species x(t) = k
end

n2 = @network_component n2 begin
    @parameters k = 2.0
    @species x(t) = k
end

@named rn = ReactionSystem([Reaction(1.0,[n1.x],[n2.x])], default_t(); systems = [n1, n2])

which gives

Model rn:
Subsystems (2): see hierarchy(rn)
  n1
  n2
Unknowns (2): see unknowns(rn)
  n1₊x(t) [defaults to k]
  n2₊x(t) [defaults to k]
Parameters (3): see parameters(rn)
  k [defaults to 2.0]
  n1₊k [defaults to 1.0]
  n2₊k [defaults to 2.0]

I don’t know why their are 3 parameters here… And

oprob = ODEProblem(complete(rn), [], (0.0, 10.0))

gives:

ODEProblem with uType Vector{Float64} and tType Float64. In-place: true
Initialization status: FULLY_DETERMINED
Non-trivial mass matrix: false
timespan: (0.0, 10.0)
u0: 2-element Vector{Float64}:
 2.0
 2.0

Maybe I did something wrong. If not, the problem may come from MTK because I could actually also reproduce the same thing:

@mtkmodel Decl1 begin
    @parameters begin
        k = 1.0
    end
    @variables begin
        x(t) = k
    end
end

@mtkmodel Decl2 begin
    @parameters begin
        k = 2.0
    end
    @variables begin
        x(t) = k
    end
end

@named m1 = Decl1()
@named m2 = Decl2()
@named sys1  = ODESystem([D(m2.x) ~ 0, D(m1.x) ~ 0], t)
prob1 = ODEProblem(complete(sys1))

gives:

ODEProblem with uType Vector{Float64} and tType Nothing. In-place: true
Initialization status: FULLY_DETERMINED
Non-trivial mass matrix: false
timespan: (nothing, nothing)
u0: 2-element Vector{Float64}:
 1.0
 1.0