rust/tests/ui/rfcs/rfc-1445-restrict-constants.../allow-use-behind-cousin-var...

60 lines
1.5 KiB
Rust

// rust-lang/rust#62614: we want to allow matching on constants of types that
// have non-structural-match variants, *if* the constant itself does not use
// any such variant.
// NOTE: for now, deliberately leaving the lint `indirect_structural_match` set
// to its default, so that we will not issue a diangostic even if
// rust-lang/rust#62614 remains an open issue.
//@ run-pass
struct Sum(u32, u32);
impl PartialEq for Sum {
fn eq(&self, other: &Self) -> bool { self.0 + self.1 == other.0 + other.1 }
}
impl Eq for Sum { }
#[derive(PartialEq, Eq)]
enum Eek {
TheConst,
UnusedByTheConst(Sum)
}
const THE_CONST: Eek = Eek::TheConst;
const SUM_THREE: Eek = Eek::UnusedByTheConst(Sum(3,0));
const EEK_ZERO: &[Eek] = &[];
const EEK_ONE: &[Eek] = &[THE_CONST];
pub fn main() {
match Eek::UnusedByTheConst(Sum(1,2)) {
ref sum if sum == &SUM_THREE => { println!("Hello 0"); }
_ => { println!("Gbye"); }
}
match Eek::TheConst {
THE_CONST => { println!("Hello 1"); }
_ => { println!("Gbye"); }
}
match & &Eek::TheConst {
& & THE_CONST => { println!("Hello 2"); }
_ => { println!("Gbye"); }
}
match & & &[][..] {
& & EEK_ZERO => { println!("Hello 3"); }
& & EEK_ONE => { println!("Gbye"); }
_ => { println!("Gbye"); }
}
match & & &[Eek::TheConst][..] {
& & EEK_ZERO => { println!("Gby"); }
& & EEK_ONE => { println!("Hello 4"); }
_ => { println!("Gbye"); }
}
}