tests/ui/coercion/method-return-trait-object-14399.rs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

//! Regression test for https://github.com/rust-lang/rust/issues/14399

//@ run-pass
// #14399
// We'd previously ICE if we had a method call whose return
// value was coerced to a trait object. (v.clone() returns Box<B1>
// which is coerced to Box<A>).


#[derive(Clone)]
struct B1;

trait A { fn foo(&self) {} } //~ WARN method `foo` is never used
impl A for B1 {}

fn main() {
    let v: Box<_> = Box::new(B1);
    let _c: Box<dyn A> = v.clone();
}