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//! Ensure that a `const fn` can match on constants of a type that is `PartialEq`
//! but not `const PartialEq`. This is accepted for backwards compatibility reasons.
//@ check-pass
#![feature(const_trait_impl)]
#[derive(Eq, PartialEq)]
pub struct Y(u8);
pub const GREEN: Y = Y(4);
pub const fn is_green(x: Y) -> bool {
match x { GREEN => true, _ => false }
}
struct CustomEq;
impl Eq for CustomEq {}
impl PartialEq for CustomEq {
fn eq(&self, _: &Self) -> bool {
false
}
}
#[derive(PartialEq, Eq)]
#[allow(unused)]
enum Foo {
Bar,
Baz,
Qux(CustomEq),
}
const BAR_BAZ: Foo = if 42 == 42 {
Foo::Bar
} else {
Foo::Qux(CustomEq) // dead arm
};
const EMPTY: &[CustomEq] = &[];
const fn test() {
// BAR_BAZ itself is fine but the enum has other variants
// that are non-structural. Still, this should be accepted.
match Foo::Qux(CustomEq) {
BAR_BAZ => panic!(),
_ => {}
}
// Similarly, an empty slice of a type that is non-structural
// is accepted.
match &[CustomEq] as &[CustomEq] {
EMPTY => panic!(),
_ => {},
}
}
fn main() {}
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