1 #![feature(box_patterns)] 2 3 #![allow(dead_code)] 4 #![deny(unreachable_patterns)] 5 6 enum Foo { A(Box<Foo>, isize), B(usize), } 7 main()8 fn main() { 9 match Foo::B(1) { 10 Foo::B(_) | Foo::A(box _, 1) => { } 11 Foo::A(_, 1) => { } //~ ERROR unreachable pattern 12 _ => { } 13 } 14 } 15