2 files changed, 55 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-57472.rs b/src/test/ui/issues/issue-57472.rs
new file mode 100644
index 00000000000..1131006374c
--- /dev/null
+++ b/src/test/ui/issues/issue-57472.rs
@@ -0,0 +1,35 @@
+#![crate_type="lib"]
+#![deny(unreachable_patterns)]
+
+mod test_struct {
+    // Test the exact copy of the minimal example
+    // posted in the issue.
+    pub struct Punned {
+        foo: [u8; 1],
+        bar: [u8; 1],
+    }
+
+    pub fn test(punned: Punned) {
+        match punned {
+            Punned { foo: [_], .. } => println!("foo"),
+            Punned { bar: [_], .. } => println!("bar"),
+            //~^ ERROR unreachable pattern [unreachable_patterns]
+        }
+    }
+}
+
+mod test_union {
+    // Test the same thing using a union.
+    pub union Punned {
+        foo: [u8; 1],
+        bar: [u8; 1],
+    }
+
+    pub fn test(punned: Punned) {
+        match punned {
+            Punned { foo: [_] } => println!("foo"),
+            Punned { bar: [_] } => println!("bar"),
+            //~^ ERROR unreachable pattern [unreachable_patterns]
+        }
+    }
+}
diff --git a/src/test/ui/issues/issue-57472.stderr b/src/test/ui/issues/issue-57472.stderr
new file mode 100644
index 00000000000..b6dd7e24941
--- /dev/null
+++ b/src/test/ui/issues/issue-57472.stderr
@@ -0,0 +1,20 @@
+error: unreachable pattern
+  --> $DIR/issue-57472.rs:15:13
+   |
+LL |             Punned { bar: [_], .. } => println!("bar"),
+   |             ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/issue-57472.rs:2:9
+   |
+LL | #![deny(unreachable_patterns)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/issue-57472.rs:31:13
+   |
+LL |             Punned { bar: [_] } => println!("bar"),
+   |             ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+