diff --git a/src/core/include/megbrain/graph/static_infer.h b/src/core/include/megbrain/graph/static_infer.h
index b79ed827303eefefb5a51afe5d024e7b71cb7106..93859bde6f8e124232969c8a18240db8662b3032 100644
--- a/src/core/include/megbrain/graph/static_infer.h
+++ b/src/core/include/megbrain/graph/static_infer.h
@@ -14,6 +14,11 @@
 #include "megbrain/tensor.h"
 
 namespace mgb {
+
+namespace imperative {
+    class ProxyGraph;
+} // namespace imperative
+
 namespace cg {
 
 class VarNode;
@@ -50,6 +55,7 @@ namespace static_infer {
         const DeviceTensorND *m_value = nullptr;
 
         friend class StaticInferManagerImpl;
+        friend class imperative::ProxyGraph;
 
         public:
             /*!