And you wanted to make sure that func2 and func3 can only be called after func1 has been called.
A wrapper on the output of func1 here would be awkward because then you return Wrapper<Func1Done>(bar0). But func2 does not even need a bar0 and neither does func3.
So the solution is to return (bar0, Wrapper<Func1Done>) from func1 where
func1(foo_0) -> bar0
func2(foo_1, foo_2) -> bar1
func3(foo_3, foo_3) -> bar2
And you wanted to make sure that func2 and func3 can only be called after func1 has been called.
A wrapper on the output of func1 here would be awkward because then you return Wrapper<Func1Done>(bar0). But func2 does not even need a bar0 and neither does func3.
So the solution is to return (bar0, Wrapper<Func1Done>) from func1 where
struct Wrapper<T>(//cheating ())