diff --git a/python/mxnet/_numpy_op_doc.py b/python/mxnet/_numpy_op_doc.py
index fc8fac19d7ad..9e237cb0049b 100644
--- a/python/mxnet/_numpy_op_doc.py
+++ b/python/mxnet/_numpy_op_doc.py
@@ -1122,4 +1122,3 @@ def _np_diag(array, k = 0):
            [0, 0, 8]])
     """
     pass
-
diff --git a/src/operator/numpy/np_matrix_op-inl.h b/src/operator/numpy/np_matrix_op-inl.h
index a98a582c9ad8..508968718af0 100644
--- a/src/operator/numpy/np_matrix_op-inl.h
+++ b/src/operator/numpy/np_matrix_op-inl.h
@@ -1065,7 +1065,7 @@ void NumpyDiagOpImpl(const TBlob &in_data,
                      index_t dsize,
                      const int &k,
                      mxnet_op::Stream<xpu> *s,
-                     const std::vector<OpReqType> &req) {
+                     const OpReqType &req) {
   using namespace mxnet_op;
   using namespace mshadow;
   if (ishape.ndim() > 1) {
@@ -1084,8 +1084,8 @@ void NumpyDiagOpImpl(const TBlob &in_data,
     }
 
     MSHADOW_TYPE_SWITCH(out_data.type_flag_, DType, {
-      MXNET_ASSIGN_REQ_SWITCH(req[0], req_type, {
-        if (back && req[0] != kAddTo && req[0] != kNullOp) {
+      MXNET_ASSIGN_REQ_SWITCH(req, req_type, {
+        if (back && req != kAddTo && req != kNullOp) {
           out_data.FlatTo1D<xpu, DType>(s) = 0;
         }
 
@@ -1096,7 +1096,7 @@ void NumpyDiagOpImpl(const TBlob &in_data,
     });
   } else {
     MSHADOW_TYPE_SWITCH(out_data.type_flag_, DType, {
-      MXNET_ASSIGN_REQ_SWITCH(req[0], req_type, {
+      MXNET_ASSIGN_REQ_SWITCH(req, req_type, {
         Kernel<diag_gen<req_type, back>, xpu>::Launch(
             s, dsize, out_data.dptr<DType>(), in_data.dptr<DType>(),
             Shape2(oshape[0], oshape[1]), k);
@@ -1125,7 +1125,7 @@ void NumpyDiagOpForward(const nnvm::NodeAttrs &attrs,
   const NumpyDiagParam &param = nnvm::get<NumpyDiagParam>(attrs.parsed);
 
   NumpyDiagOpImpl<xpu, false>(in_data, out_data, ishape, oshape,
-                                 out_data.Size(), param.k, s, req);
+                              out_data.Size(), param.k, s, req[0]);
 }
 
 template <typename xpu>
@@ -1147,7 +1147,7 @@ void NumpyDiagOpBackward(const nnvm::NodeAttrs &attrs,
   const NumpyDiagParam &param = nnvm::get<NumpyDiagParam>(attrs.parsed);
 
   NumpyDiagOpImpl<xpu, true>(in_data, out_data, oshape, ishape,
-                                in_data.Size(), param.k, s, req);
+                             in_data.Size(), param.k, s, req[0]);
 }
 
 }  // namespace op
diff --git a/tests/python/unittest/test_numpy_interoperability.py b/tests/python/unittest/test_numpy_interoperability.py
index 94783defe83b..486722d15057 100644
--- a/tests/python/unittest/test_numpy_interoperability.py
+++ b/tests/python/unittest/test_numpy_interoperability.py
@@ -58,7 +58,6 @@ def get_workloads(name):
 
 
 def _add_workload_diag():
-
     def get_mat(n):
         data = _np.arange(n)
         data = _np.add.outer(data, data)
@@ -67,7 +66,7 @@ def get_mat(n):
     A = np.array([[1, 2], [3, 4], [5, 6]])
     vals = (100 * np.arange(5)).astype('l')
     vals_c = (100 * np.array(get_mat(5)) + 1).astype('l')
-    vals_f = _np.array((100 * get_mat(5) + 1), order = 'F', dtype = 'l')
+    vals_f = _np.array((100 * get_mat(5) + 1), order ='F', dtype ='l')
     vals_f = np.array(vals_f)
 
     OpArgMngr.add_workload('diag', A, k= 2)
diff --git a/tests/python/unittest/test_numpy_op.py b/tests/python/unittest/test_numpy_op.py
index 003962ba28c0..39f462379940 100644
--- a/tests/python/unittest/test_numpy_op.py
+++ b/tests/python/unittest/test_numpy_op.py
@@ -4510,7 +4510,7 @@ def hybrid_forward(self, F, a):
         if hybridize:
             test_diag.hybridize()
 
-        x = np.random.uniform(-1.0, 1.0, size=shape).astype(dtype)
+        x = np.random.uniform(-2.0, 2.0, size=shape).astype(dtype) if len(shape) != 0 else np.array(())
         x.attach_grad()
 
         np_out = _np.diag(x.asnumpy(), k)