Add a test for rust-lang#27054

Author: varkor

src/test/ui/primitive-binop-lhs-mut.rs

@@ -0,0 +1,6 @@
+// run-pass
+
+fn main() {
+    let x = Box::new(0);
+    assert_eq!(0, *x + { drop(x); let _ = Box::new(main); 0 });
+}