diff --git a/Scope.h b/Scope.h
index 651bb83..b5c65d6 100644
--- a/Scope.h
+++ b/Scope.h
@@ -21,6 +21,7 @@
 
     void dump(Formatter &out) const override;
     bool isScope() const override;
+    bool containsSingleInterface(std::string *ifaceName) const;
 
 private:
     Vector<Type *> mTypes;