add missing include file

Summary: Without this, we couldn't include `for_each.h` before generated `_for_each_field.h`. Otherwise it's build-error due to missing type.

Reviewed By: iahs

Differential Revision: D23250681

fbshipit-source-id: 70455a2b1c0be919c253ded55ed3b982a2ea8d0e

thrift/lib/cpp2/visitation/metadata.h

@@ -17,6 +17,7 @@
 #pragma once
 
 #include <folly/Indestructible.h>
+#include <thrift/lib/cpp2/gen/module_metadata_h.h>
 #include <thrift/lib/thrift/gen-cpp2/metadata_types.h>
 
 namespace apache {

thrift/test/visitation_for_each_include_order_test.cpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Test whether it works if we include for_each.h first.
+#include <thrift/lib/cpp2/visitation/for_each.h>
+
+#include <thrift/test/gen-cpp2/reflection_for_each_field.h>
+
+#include <folly/String.h>
+#include <folly/portability/GTest.h>
+
+using namespace apache::thrift;
+using namespace test_cpp2::cpp_reflection;
+
+TEST(structA, test) {
+  structA s;
+  s.a_ref() = 1;
+  s.b_ref() = "1";
+  for_each_field(s, [](auto&&, auto ref) {
+    EXPECT_EQ(folly::to<std::string>(*ref), "1");
+    ref = folly::to<typename decltype(ref)::value_type>(2);
+  });
+  EXPECT_EQ(s.a_ref(), 2);
+  EXPECT_EQ(s.b_ref(), "2");
+}