Add unnecessary copy check to clang-tidy

.clang-tidy

@@ -54,7 +54,7 @@ Checks: >
 
 # In order to trigger an error, you must have a rule defined both in checks and in this section.
 WarningsAsErrors: >
-    cppcoreguidelines-no-malloc
+    cppcoreguidelines-no-malloc, performance-unnecessary-copy-initialization
 
 # Todo: define a better regex match that includes most project headers, but excludes third party
 # code.

src/operator/contrib/roi_align.cc

@@ -422,7 +422,7 @@ void ROIAlignForwardCompute(const nnvm::NodeAttrs& attrs,
   CHECK_EQ(out_data.size(), expected_out);
   CHECK_EQ(out_data[roialign::kOut].shape_[0], in_data[roialign::kBox].shape_[0]);
 
-  const ROIAlignParam param& = nnvm::get<ROIAlignParam>(attrs.parsed);
+  const ROIAlignParam& param = nnvm::get<ROIAlignParam>(attrs.parsed);
 
   const int count = out_data[roialign::kOut].Size();
   // const int num_rois = in_data[roialign::kBox].size(0);