diff --git a/parse.y b/parse.y
index 948437000..787f409cb 100644
--- a/parse.y
+++ b/parse.y
@@ -1044,7 +1044,11 @@ data_type /* IEEE1800-2005: A.2.2.1 */
 	$$ = tmp;
       }
   | struct_data_type
-      { $$ = $1; }
+      { if (!$1->packed_flag) {
+	      yyerror(@1, "sorry: Unpacked structs not supported.");
+	}
+	$$ = $1;
+      }
   | enum_data_type
       { $$ = $1; }
   | atom2_type signed_unsigned_opt
diff --git a/pform_struct_type.cc b/pform_struct_type.cc
index 766fc77e3..433e66a91 100644
--- a/pform_struct_type.cc
+++ b/pform_struct_type.cc
@@ -79,8 +79,8 @@ static void pform_set_struct_type(struct_type_t*struct_type, perm_string name, N
 	    return;
       }
 
-	// For now, can only handle packed structs.
-      ivl_assert(*struct_type, 0);
+	// For now, can only handle packed structs. The parser generates
+	// a "sorry" message, so no need to do anything here.
 }
 
 void pform_set_struct_type(struct_type_t*struct_type, list<perm_string>*names, NetNet::Type net_type, list<named_pexpr_t>*attr)