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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:03 +0000 |
commit | 64d98f8ee037282c35007b64c2649055c56af1db (patch) | |
tree | 5492bcf97fce41ee1c0b1cc2add283f3e66cdab0 /tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs | |
parent | Adding debian version 1.67.1+dfsg1-1. (diff) | |
download | rustc-64d98f8ee037282c35007b64c2649055c56af1db.tar.xz rustc-64d98f8ee037282c35007b64c2649055c56af1db.zip |
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs')
-rw-r--r-- | tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs b/tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs new file mode 100644 index 000000000..46d8ee3b6 --- /dev/null +++ b/tests/ui/rfc-1445-restrict-constants-in-patterns/issue-62307-match-ref-ref-forbidden-without-eq.rs @@ -0,0 +1,43 @@ +// RFC 1445 introduced `#[structural_match]`; this attribute must +// appear on the `struct`/`enum` definition for any `const` used in a +// pattern. +// +// This is our (forever-unstable) way to mark a datatype as having a +// `PartialEq` implementation that is equivalent to recursion over its +// substructure. This avoids (at least in the short term) any need to +// resolve the question of what semantics is used for such matching. +// (See RFC 1445 for more details and discussion.) + +// Issue 62307 pointed out a case where the structural-match checking +// was too shallow. +#![warn(indirect_structural_match, nontrivial_structural_match)] +// run-pass + +#[derive(Debug)] +struct B(i32); + +// Overriding `PartialEq` to use this strange notion of "equality" exposes +// whether `match` is using structural-equality or method-dispatch +// under the hood, which is the antithesis of rust-lang/rfcs#1445 +impl PartialEq for B { + fn eq(&self, other: &B) -> bool { std::cmp::min(self.0, other.0) == 0 } +} + +fn main() { + const RR_B0: & & B = & & B(0); + const RR_B1: & & B = & & B(1); + + match RR_B0 { + RR_B1 => { println!("CLAIM RR0: {:?} matches {:?}", RR_B1, RR_B0); } + //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]` + //~| WARN this was previously accepted + _ => { } + } + + match RR_B1 { + RR_B1 => { println!("CLAIM RR1: {:?} matches {:?}", RR_B1, RR_B1); } + //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]` + //~| WARN this was previously accepted + _ => { } + } +} |