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|
// This test of structural match checking enumerates the different kinds of
// const definitions, collecting cases where the const pattern is rejected.
//
// Note: Even if a non-structural-match type is part of an expression in a
// const's definition, that does not necessarily disqualify the const from being
// a match pattern: in principle, we just need the types involved in the final
// value to be structurally matchable.
// See also RFC 1445
#![feature(type_ascription)]
#![warn(indirect_structural_match)]
//~^ NOTE lint level is defined here
#[derive(Copy, Clone, Debug)]
struct NoPartialEq;
#[derive(Copy, Clone, Debug)]
struct NoDerive;
// This impl makes `NoDerive` irreflexive.
impl PartialEq for NoDerive { fn eq(&self, _: &Self) -> bool { false } }
impl Eq for NoDerive { }
type OND = Option<NoDerive>;
struct TrivialEq(OND);
// This impl makes `TrivialEq` trivial.
impl PartialEq for TrivialEq { fn eq(&self, _: &Self) -> bool { true } }
impl Eq for TrivialEq { }
fn main() {
#[derive(PartialEq, Eq, Debug)]
enum Derive<X> { Some(X), None, }
const ENUM: Derive<NoDerive> = Derive::Some(NoDerive);
match Derive::Some(NoDerive) { ENUM => dbg!(ENUM), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const FIELD: OND = TrivialEq(Some(NoDerive)).0;
match Some(NoDerive) { FIELD => dbg!(FIELD), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const NO_DERIVE_SOME: OND = Some(NoDerive);
const INDIRECT: OND = NO_DERIVE_SOME;
match Some(NoDerive) {INDIRECT => dbg!(INDIRECT), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const TUPLE: (OND, OND) = (None, Some(NoDerive));
match (None, Some(NoDerive)) { TUPLE => dbg!(TUPLE), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const TYPE_ASCRIPTION: OND = type_ascribe!(Some(NoDerive), OND);
match Some(NoDerive) { TYPE_ASCRIPTION => dbg!(TYPE_ASCRIPTION), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const ARRAY: [OND; 2] = [None, Some(NoDerive)];
match [None, Some(NoDerive)] { ARRAY => dbg!(ARRAY), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const REPEAT: [OND; 2] = [Some(NoDerive); 2];
match [Some(NoDerive); 2] { REPEAT => dbg!(REPEAT), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
//~| ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
trait Trait: Sized { const ASSOC: Option<Self>; }
impl Trait for NoDerive { const ASSOC: Option<NoDerive> = Some(NoDerive); }
match Some(NoDerive) { NoDerive::ASSOC => dbg!(NoDerive::ASSOC), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const BLOCK: OND = { NoDerive; Some(NoDerive) };
match Some(NoDerive) { BLOCK => dbg!(BLOCK), _ => panic!("whoops"), };
//~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
const ADDR_OF: &OND = &Some(NoDerive);
match &Some(NoDerive) { ADDR_OF => dbg!(ADDR_OF), _ => panic!("whoops"), };
//~^ WARN must be annotated with `#[derive(PartialEq, Eq)]`
//~| NOTE the traits must be derived
//~| NOTE StructuralEq.html for details
//~| WARN previously accepted by the compiler but is being phased out
//~| NOTE for more information, see issue #62411
}
|
