diff --git a/src/test/ui/closures/issue-84044-drop-non-mut.rs b/src/test/ui/closures/issue-84044-drop-non-mut.rs
new file mode 100644
index 0000000000000..aed7750f1b9df
--- /dev/null
+++ b/src/test/ui/closures/issue-84044-drop-non-mut.rs
@@ -0,0 +1,6 @@
+// #84044: This used to ICE.
+
+fn main() {
+    let f = || {};
+    drop(&mut f); //~ ERROR cannot borrow `f` as mutable, as it is not declared as mutable
+}
diff --git a/src/test/ui/closures/issue-84044-drop-non-mut.stderr b/src/test/ui/closures/issue-84044-drop-non-mut.stderr
new file mode 100644
index 0000000000000..c0bfad263f178
--- /dev/null
+++ b/src/test/ui/closures/issue-84044-drop-non-mut.stderr
@@ -0,0 +1,11 @@
+error[E0596]: cannot borrow `f` as mutable, as it is not declared as mutable
+  --> $DIR/issue-84044-drop-non-mut.rs:5:10
+   |
+LL |     let f = || {};
+   |         - help: consider changing this to be mutable: `mut f`
+LL |     drop(&mut f);
+   |          ^^^^^^ cannot borrow as mutable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0596`.