Function canrun::state::constraints::resolve_1

pub fn resolve_1<'a, A, D>(
    val: &Val<A>, 
    state: &State<'a, D>
) -> Result<Rc<A>, VarWatch> where
    A: Debug,
    D: DomainType<'a, A>, 

Resolve one Val or return an Err(VarWatch) in a Constraint.