variables coming from observed kwarg not added to var_to_name

[isaacsas]

Following the tutorials this works:

using ModelingToolkit
@variables t x(t) 
@parameters τ   
D = Differential(t) 
@variables RHS(t)
@named fol_separate = ODESystem([ RHS  ~ (1 - x)/τ,
                                  D(x) ~ RHS ])
fol_simplified = structural_simplify(fol_separate)

with

julia> fol_simplified.RHS
fol_separate₊RHS(t)

however

@named fol = ODESystem(equations(fol_simplified), ModelingToolkit.get_iv(fol_simplified); observed=observed(fol_simplified))

gives

julia> fol.RHS
fol₊RHS(t) ~ (1 - fol₊x(t)) / fol₊τ

Should the ODESystem constructor be detecting the lhs of observed equations and calling process_variables! on them?

edit: I guess collect_var_to_name! is what should actually be called on the lhs.

[isaacsas]

If the fix is what I mention about adding the lhs of observed equations I'm happy to put in a PR. (I'm just not sure if we can assume observed eqs are always of the form variable ~ symbolic_expression.)

[isaacsas]

Should be closed by #1343