diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
index fc3f97b59..ade20413d 100644
--- a/src/idl_parser.cpp
+++ b/src/idl_parser.cpp
@@ -745,6 +745,10 @@ CheckedError Parser::ParseField(StructDef &struct_def) {
   }
 
   if (typefield) {
+    if (!IsScalar(typefield->value.type.base_type)) {
+      // this is a union vector field
+      typefield->required = field->required;
+    }
     // If this field is a union, and it has a manually assigned id,
     // the automatically added type field should have an id as well (of N - 1).
     auto attr = field->attributes.Lookup("id");