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// Check that we can manually implement an object-unsafe trait for its trait object.
//@ revisions: current next
//@ ignore-compare-mode-next-solver (explicit revisions)
//@[next] compile-flags: -Znext-solver
//@ run-pass
#![feature(object_safe_for_dispatch)]
trait Bad {
fn stat() -> char {
'A'
}
fn virt(&self) -> char {
'B'
}
fn indirect(&self) -> char {
Self::stat()
}
}
trait Good {
fn good_virt(&self) -> char { //~ WARN methods `good_virt` and `good_indirect` are never used
panic!()
}
fn good_indirect(&self) -> char {
panic!()
}
}
impl<'a> Bad for dyn Bad + 'a {
fn stat() -> char {
'C'
}
fn virt(&self) -> char {
'D'
}
}
struct Struct {}
impl Bad for Struct {}
impl Good for Struct {}
fn main() {
let s = Struct {};
let mut res = String::new();
// Directly call static.
res.push(Struct::stat()); // "A"
res.push(<dyn Bad>::stat()); // "AC"
let good: &dyn Good = &s;
// These look similar enough...
let bad = unsafe { std::mem::transmute::<&dyn Good, &dyn Bad>(good) };
// Call virtual.
res.push(s.virt()); // "ACB"
res.push(bad.virt()); // "ACBD"
// Indirectly call static.
res.push(s.indirect()); // "ACBDA"
res.push(bad.indirect()); // "ACBDAC"
assert_eq!(&res, "ACBDAC");
}
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