2 files changed, 37 insertions, 0 deletions
diff --git a/tests/ui/pattern/deref-patterns/ref-mut.rs b/tests/ui/pattern/deref-patterns/ref-mut.rs
new file mode 100644
index 00000000000..1918008a761
--- /dev/null
+++ b/tests/ui/pattern/deref-patterns/ref-mut.rs
@@ -0,0 +1,17 @@
+#![feature(deref_patterns)]
+//~^ WARN the feature `deref_patterns` is incomplete
+
+use std::rc::Rc;
+
+fn main() {
+    match &mut vec![1] {
+        deref!(x) => {}
+        _ => {}
+    }
+
+    match &mut Rc::new(1) {
+        deref!(x) => {}
+        //~^ ERROR the trait bound `Rc<{integer}>: DerefMut` is not satisfied
+        _ => {}
+    }
+}
diff --git a/tests/ui/pattern/deref-patterns/ref-mut.stderr b/tests/ui/pattern/deref-patterns/ref-mut.stderr
new file mode 100644
index 00000000000..41f1c3061ce
--- /dev/null
+++ b/tests/ui/pattern/deref-patterns/ref-mut.stderr
@@ -0,0 +1,20 @@
+warning: the feature `deref_patterns` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/ref-mut.rs:1:12
+   |
+LL | #![feature(deref_patterns)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: see issue #87121 <https://github.com/rust-lang/rust/issues/87121> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0277]: the trait bound `Rc<{integer}>: DerefMut` is not satisfied
+  --> $DIR/ref-mut.rs:13:9
+   |
+LL |         deref!(x) => {}
+   |         ^^^^^^^^^ the trait `DerefMut` is not implemented for `Rc<{integer}>`
+   |
+   = note: this error originates in the macro `deref` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 1 previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0277`.