diff --git a/python/tvm/relay/frontend/onnx.py b/python/tvm/relay/frontend/onnx.py
index 527a1ed2f07b..245b3853ae90 100644
--- a/python/tvm/relay/frontend/onnx.py
+++ b/python/tvm/relay/frontend/onnx.py
@@ -57,8 +57,7 @@ def __setitem__(self, item, value):
         if isinstance(item, int):
             self.input_dict[self.input_keys[item]] = value
         elif isinstance(item, str):
-            if item not in self.input_dict:
-                self.input_keys.append(item)
+            self.input_keys.append(item)
             self.input_dict[item] = value
         else:
             raise ValueError("Only integer and string indexed writes allowed.")
diff --git a/tests/python/frontend/onnx/test_forward.py b/tests/python/frontend/onnx/test_forward.py
index 2c0849451a25..c06aa50538f4 100644
--- a/tests/python/frontend/onnx/test_forward.py
+++ b/tests/python/frontend/onnx/test_forward.py
@@ -1366,16 +1366,16 @@ def test_binary_ops():
     dtype = "float32"
     out_shape = in_shape
 
-    def verify_binary_ops(op, x, y, out_np, broadcast=None):
+    def verify_binary_ops(op, x, y, out_np, x_name='in1', y_name='in2', broadcast=None):
         if broadcast is None:
-            z = helper.make_node(op, ['in1', 'in2'], ['out'])
+            z = helper.make_node(op, [x_name, y_name], ['out'])
         else:
-            z = helper.make_node(op, ['in1', 'in2'], ['out'], broadcast=1)
+            z = helper.make_node(op, [x_name, y_name], ['out'], broadcast=1)
         graph = helper.make_graph([z],
                                   '_test',
-                                  inputs=[helper.make_tensor_value_info("in1",
+                                  inputs=[helper.make_tensor_value_info(x_name,
                                                                         TensorProto.FLOAT, list(in_shape)),
-                                          helper.make_tensor_value_info("in2",
+                                          helper.make_tensor_value_info(y_name,
                                                                         TensorProto.FLOAT, list(in_shape))],
                                   outputs=[helper.make_tensor_value_info("out",
                                                                          TensorProto.FLOAT, list(out_shape))])
@@ -1393,6 +1393,7 @@ def verify_binary_ops(op, x, y, out_np, broadcast=None):
     verify_binary_ops("Sub", x, z, x - z, broadcast=True)
     verify_binary_ops("Mul", x, y, x * y, broadcast=None)
     verify_binary_ops("Mul", x, z,  x * z, broadcast=True)
+    verify_binary_ops("Mul", x, x, x * x, x_name='in1', y_name='in1', broadcast=None)
     verify_binary_ops("Div", x, y, x / y, broadcast=None)
     verify_binary_ops("Div", x, z, x / z, broadcast=True)
     verify_binary_ops("Sum", x, y, x + y, broadcast=None)