diff --git a/mlir/include/mlir/IR/OperationSupport.h b/mlir/include/mlir/IR/OperationSupport.h
--- a/mlir/include/mlir/IR/OperationSupport.h
+++ b/mlir/include/mlir/IR/OperationSupport.h
@@ -272,6 +272,7 @@
 
   /// Add an attribute with the specified name.
   void append(Identifier name, Attribute attr) {
+    assert(attr && "unexpected null attribute");
     append(NamedAttribute(name, attr));
   }