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// 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.
//
// It is also interesting because the access to the corrupted data
// occurs in the pattern-match itself, and not in the guard
// expression.
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
} => {}
// this segfaults if we corrupted the discriminant, because
// the compiler gets to *assume* that it cannot be the `None`
// case, even though that was the effect of the guard.
&mut Some(&2)
if {
panic!()
} => {}
_ => panic!("unreachable"),
}
}
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