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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 a borrow of **x is untracked, because **x is
// immutable. However, for matches we care that **x refers to the same value
// until we have chosen a match arm.
struct ForceFnOnce;
fn main() {
let mut x = &mut &Some(&2);
let force_fn_once = ForceFnOnce;
match **x {
None => panic!("unreachable"),
Some(&_) if {
// ForceFnOnce needed to exploit #27282
(|| { *x = &None; drop(force_fn_once); })();
//~^ ERROR cannot mutably borrow `x` in match guard [E0510]
false
} => {}
Some(&a) if { // this binds to garbage if we've corrupted discriminant
println!("{}", a);
panic!()
} => {}
_ => panic!("unreachable"),
}
}
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