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