parameters returns non-unique set of parameters

[isaacsas]

Should the parameters function have redundant entires (i.e. not call unique as states does), or am I using ParentScope incorrectly?

@parameters p1 p2
@variables t v1(t) v2(t)
eqs1 = [v1 ~ p1]
eqs2 = [ParentScope(v1) ~ ParentScope(p1)*v2 + p2]
@named osys2 = ODESystem(eqs2, t, [ParentScope(v1),v2],[ParentScope(p1),p2])
@named osys1 = ODESystem(eqs1, t, [v1], [p1], systems=[osys2])

then

julia> parameters(osys1)
3-element Vector{Sym{Real, Base.ImmutableDict{DataType, Any}}}:
 p1
 p1
 osys2₊p2

while states correctly gives

julia> states(osys1)
2-element Vector{Term{Real, Base.ImmutableDict{DataType, Any}}}:
 v1(t)
 osys2₊v2(t)

[ChrisRackauckas]

It should be unique. How did it not be unique? That seems like an extend bug @YingboMa ?

[isaacsas]

This doesn't use extend, it is just that states applies a unique filter before returning but parameters (and some other accessors) does not.