another code-generation issue with value types

[nano-o]

Hello, ivyc generates invalid C++ code on the example below. Should it be working?

instance elem : iterable
object obj = {
    type my_set = struct {
        member(N:elem) : bool
    }
    relation empty(S:my_set)
    definition empty(s:my_set) = forall N . ~member(s,N)
    export action emptyset returns (s:my_set) = {
        member(s,N) := false;
    }
    export action add(s:my_set, n:elem) returns (s:my_set) = {
        if ~member(s,n) {
            member(s,N) := member(s,N) | N = n
        }
    }
}
extract code = obj, elem

[kenmcmil]

That's a really painful bug. Structs have to have computable equality. So if a struct has a function member, then the function's domain has to be of a type that is iterable. So far, so good. The problem is that the equality comparator is a static overload in C++. But the size parameter of type elem is a non-static member of the class, so the equality comparator can't access it to iterate over elem. So there are few bad options:

1. Make equality comparison a non-static member function
2. Make the size parameter static
3. Store the size parameter in the struct

Probably the last is the least disruptive option. It might take a while to get this fixed, though.