src/test/ui/structs-enums/enum-nullable-simplifycfg-misopt.rs

// run-pass
#![feature(box_syntax)]

/*!
 * This is a regression test for a bug in LLVM, fixed in upstream r179587,
 * where the switch instructions generated for destructuring enums
 * represented with nullable pointers could be misoptimized in some cases.
 */

enum List<X> { Nil, Cons(X, Box<List<X>>) }
pub fn main() {
    match List::Cons(10, box List::Nil) {
        List::Cons(10, _) => {}
        List::Nil => {}
        _ => panic!()
    }
}