Function illicit::expect [−][src]
pub fn expect<E>() -> impl Deref<Target = E> + 'static where
E: Any + Debug + 'static,
Returns a reference to a value in the current environment, as
get
does, but panics if the value has not been set.
The panic message includes the stack of current Layer
s
and their contents.
Examples
let msg = "hello!"; illicit::Layer::new().offer(String::from(msg)).enter(|| { assert_eq!(&*illicit::expect::<String>(), msg); });
Panics if the requested type is not in the environment:
ⓘ
println!("{}", &*illicit::expect::<String>());