diff --git a/mlir/include/mlir/IR/OpBase.td b/mlir/include/mlir/IR/OpBase.td
--- a/mlir/include/mlir/IR/OpBase.td
+++ b/mlir/include/mlir/IR/OpBase.td
@@ -2861,6 +2861,7 @@
       AttrOrTypeDef<"Attr", name, traits, baseCppClass> {
   // The name of the C++ Attribute class.
   string cppClassName = name # "Attr";
+  string storageType = dialect.cppNamespace # "::" # name # "Attr";
 
   // The underlying C++ value type
   let returnType = dialect.cppNamespace # "::" # cppClassName;