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-rw-r--r--src/test/ui/rfc-1445-restrict-constants-in-patterns/phantom-data-is-structurally-matchable.rs53
1 files changed, 53 insertions, 0 deletions
diff --git a/src/test/ui/rfc-1445-restrict-constants-in-patterns/phantom-data-is-structurally-matchable.rs b/src/test/ui/rfc-1445-restrict-constants-in-patterns/phantom-data-is-structurally-matchable.rs
new file mode 100644
index 000000000..50f91420c
--- /dev/null
+++ b/src/test/ui/rfc-1445-restrict-constants-in-patterns/phantom-data-is-structurally-matchable.rs
@@ -0,0 +1,53 @@
+// run-pass
+
+// This file checks that `PhantomData` is considered structurally matchable.
+
+use std::marker::PhantomData;
+
+fn main() {
+ let mut count = 0;
+
+ // A type which is not structurally matchable:
+ struct NotSM;
+
+ // And one that is:
+ #[derive(PartialEq, Eq)]
+ struct SM;
+
+ // Check that SM is structural-match:
+ const CSM: SM = SM;
+ match SM {
+ CSM => count += 1,
+ };
+
+ // Check that PhantomData<T> is structural-match even if T is not.
+ const CPD1: PhantomData<NotSM> = PhantomData;
+ match PhantomData {
+ CPD1 => count += 1,
+ };
+
+ // Check that PhantomData<T> is structural-match when T is.
+ const CPD2: PhantomData<SM> = PhantomData;
+ match PhantomData {
+ CPD2 => count += 1,
+ };
+
+ // Check that a type which has a PhantomData is structural-match.
+ #[derive(PartialEq, Eq, Default)]
+ struct Foo {
+ alpha: PhantomData<NotSM>,
+ beta: PhantomData<SM>,
+ }
+
+ const CFOO: Foo = Foo {
+ alpha: PhantomData,
+ beta: PhantomData,
+ };
+
+ match Foo::default() {
+ CFOO => count += 1,
+ };
+
+ // Final count must be 4 now if all
+ assert_eq!(count, 4);
+}