Drop ownership from "method position".
Normally, unowned data is automatically dropped at the end of its residing
block. We can also ignore unuseful return values with ;
, which is
essentially a T -> ()
transformation. However, there are cases where we
wish to drop ownership and return cleanly with a ()
, but don't want to
involve ;
(such as in closures or simple match
arms). We could use
[std::mem::drop
] for this, but drop
is a function, not a method, and
would visually mar a nice chain of method calls.
Hence the [Disown
] trait and its method disown
. It is drop
, but in
"method position".
use disown::Disown;
use std::collections::HashSet;
enum Person {
Bob,
Sam,
}
let mut set = HashSet::new();
let person = Person::Bob;
match person {
Person::Bob => set.insert(0).disown(),
Person::Sam => set.insert(1).disown(),
}
HashSet::insert
returns a bool
, not ()
, and the above code would not
compile without opening a pair of {}
and using a ;
, which doesn't look
as nice.
License: MIT