Parse operators
diff --git a/src/expr.rs b/src/expr.rs
index bb8b469..1f4e1bd 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -1152,7 +1152,7 @@
             )
             |
             do_parse!(
-                op: call!(BinOp::parse_assign_op) >>
+                op: shim!(BinOp::parse_assign_op) >>
                 // Recurse into self to parse right-associative operator.
                 rhs: call!(assign_expr, allow_struct, true) >>
                 ({