34 lines
1.1 KiB
Rust
34 lines
1.1 KiB
Rust
// This is testing an attempt to corrupt the discriminant of the match
|
|
// arm in a guard, followed by an attempt to continue matching on that
|
|
// corrupted discriminant in the remaining match arms.
|
|
//
|
|
// Basically this is testing that our new NLL feature of emitting a
|
|
// fake read on each match arm is catching cases like this.
|
|
//
|
|
// This case is interesting because it includes a guard that
|
|
// diverges, and therefore a single final fake-read at the very end
|
|
// after the final match arm would not suffice.
|
|
|
|
#![feature(nll)]
|
|
|
|
struct ForceFnOnce;
|
|
|
|
fn main() {
|
|
let mut x = &mut Some(&2);
|
|
let force_fn_once = ForceFnOnce;
|
|
match x {
|
|
&mut None => panic!("unreachable"),
|
|
&mut Some(&_) if {
|
|
// ForceFnOnce needed to exploit #27282
|
|
(|| { *x = None; drop(force_fn_once); })();
|
|
//~^ ERROR cannot mutably borrow `x` in match guard [E0510]
|
|
false
|
|
} => {}
|
|
&mut Some(&a) if { // this binds to garbage if we've corrupted discriminant
|
|
println!("{}", a);
|
|
panic!()
|
|
} => {}
|
|
_ => panic!("unreachable"),
|
|
}
|
|
}
|