Struct Deps 

pub struct Deps<'a, S, Q> {
    pub store: &'a AuthStore,
    pub source: &'a S,
    pub quirks_source: &'a Q,
    pub env_is_set: &'a dyn Fn(&str) -> bool,
    /* private fields */
}

What the wizard needs from the outside world.

Bundled rather than threaded one by one: every field here exists so a test can supply a stand-in - the model listing, the quirks registry, and whether an environment variable is set are the three things that would otherwise reach the network or the process environment from inside a unit test.

The bounds sit on the functions that use the fields rather than on the struct: a bound on a data declaration has to be repeated at every mention of the type without constraining anything the fields do.

Fields

store: &'a AuthStore

Keys already held for this machine.

source: &'a S

What models an endpoint serves.

quirks_source: &'a Q

What quirks a chosen model has.

env_is_set: &'a dyn Fn(&str) -> bool

Whether an environment variable is set.