> This makes sense this we can't gimplify a placeholder expression. So
> this seems that when i make a constructor for the QUAL_UNION_TYPE i
> must iterate the fields and replace the placeholder_expr to have a
> reference to the discriminant via another COMPONENT_REF. Though does
> this mean for th
> That makes sense during construction we also know what the value of
> the discriminant is. What does the Ada front-end replace the
> placeholder_exprs with? Can it simply be the value of the discriminant
> at constructor? I haven't tried that.
Ultimately all PLACEHOLDER_EXPRs need to be replaced
