1 files changed, 83 insertions, 0 deletions
diff --git a/src/test/ui/consts/const_in_pattern/reject_non_structural.rs b/src/test/ui/consts/const_in_pattern/reject_non_structural.rs
new file mode 100644
index 000000000..7a8169bec
--- /dev/null
+++ b/src/test/ui/consts/const_in_pattern/reject_non_structural.rs
@@ -0,0 +1,83 @@
+// 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)]`
+
+    const FIELD: OND = TrivialEq(Some(NoDerive)).0;
+    match Some(NoDerive) { FIELD => dbg!(FIELD), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    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)]`
+
+    const TUPLE: (OND, OND) = (None, Some(NoDerive));
+    match (None, Some(NoDerive)) { TUPLE => dbg!(TUPLE), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    const TYPE_ASCRIPTION: OND = Some(NoDerive): OND;
+    match Some(NoDerive) { TYPE_ASCRIPTION => dbg!(TYPE_ASCRIPTION), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    const ARRAY: [OND; 2] = [None, Some(NoDerive)];
+    match [None, Some(NoDerive)] { ARRAY => dbg!(ARRAY), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    const REPEAT: [OND; 2] = [Some(NoDerive); 2];
+    match [Some(NoDerive); 2] { REPEAT => dbg!(REPEAT), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+    //~| ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    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)]`
+
+    const BLOCK: OND = { NoDerive; Some(NoDerive) };
+    match Some(NoDerive) { BLOCK => dbg!(BLOCK), _ => panic!("whoops"), };
+    //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
+
+    const ADDR_OF: &OND = &Some(NoDerive);
+    match &Some(NoDerive) { ADDR_OF => dbg!(ADDR_OF), _ => panic!("whoops"), };
+    //~^ WARN must be annotated with `#[derive(PartialEq, Eq)]`
+    //~| WARN previously accepted by the compiler but is being phased out
+    //~| NOTE for more information, see issue #62411
+}