Can I impose a super type for an existing struct?

[giancarloantonucci]

@Henrique_Becker

It seems to me that you have in your mind the limitation that your function/solver can only take concrete subtypes of InitialValueProblem . Why do not define (or just let the user define) a new method of the same function/solver which takes an OrdinaryDiffEq.ODEProblem instead of a subtype of InitialValueProblem ? Functions are extensible.

The problem with this approach in my case is that the solver calls a plethora of other functions which all take InitialValueProblem as input.

I think the second option you’ve suggested is the best way to proceed for me.