1 files changed, 31 insertions, 0 deletions
diff --git a/tests/ui/consts/mozjs-error.rs b/tests/ui/consts/mozjs-error.rs
new file mode 100644
index 00000000000..7edcadbf2cb
--- /dev/null
+++ b/tests/ui/consts/mozjs-error.rs
@@ -0,0 +1,31 @@
+// run-pass
+#![allow(dead_code)]
+#![allow(non_upper_case_globals)]
+
+struct CustomAutoRooterVFTable {
+    trace: unsafe extern "C" fn(this: *mut i32, trc: *mut u32),
+}
+
+unsafe trait CustomAutoTraceable: Sized {
+    const vftable: CustomAutoRooterVFTable = CustomAutoRooterVFTable {
+        trace: Self::trace,
+    };
+
+    unsafe extern "C" fn trace(this: *mut i32, trc: *mut u32) {
+        let this = this as *const Self;
+        let this = this.as_ref().unwrap();
+        Self::do_trace(this, trc);
+    }
+
+    fn do_trace(&self, trc: *mut u32);
+}
+
+unsafe impl CustomAutoTraceable for () {
+    fn do_trace(&self, _: *mut u32) {
+        // nop
+    }
+}
+
+fn main() {
+    let _ = <()>::vftable;
+}