diff --git a/balancer/xds/edsbalancer/balancergroup.go b/balancer/xds/edsbalancer/balancergroup.go
index 10ddf3213..77b185c8b 100644
--- a/balancer/xds/edsbalancer/balancergroup.go
+++ b/balancer/xds/edsbalancer/balancergroup.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/balancergroup_test.go b/balancer/xds/edsbalancer/balancergroup_test.go
index 580d9069c..10ed684e5 100644
--- a/balancer/xds/edsbalancer/balancergroup_test.go
+++ b/balancer/xds/edsbalancer/balancergroup_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/edsbalancer.go b/balancer/xds/edsbalancer/edsbalancer.go
index ebdde63bf..8e4efcb7c 100644
--- a/balancer/xds/edsbalancer/edsbalancer.go
+++ b/balancer/xds/edsbalancer/edsbalancer.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/edsbalancer_test.go b/balancer/xds/edsbalancer/edsbalancer_test.go
index 40ae93c2d..592d95da2 100644
--- a/balancer/xds/edsbalancer/edsbalancer_test.go
+++ b/balancer/xds/edsbalancer/edsbalancer_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/test_util_test.go b/balancer/xds/edsbalancer/test_util_test.go
index ed0415d47..674a2b462 100644
--- a/balancer/xds/edsbalancer/test_util_test.go
+++ b/balancer/xds/edsbalancer/test_util_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/util.go b/balancer/xds/edsbalancer/util.go
index 46c6283f7..0b1a397f2 100644
--- a/balancer/xds/edsbalancer/util.go
+++ b/balancer/xds/edsbalancer/util.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/edsbalancer/util_test.go b/balancer/xds/edsbalancer/util_test.go
index fa5338f82..68471b6c1 100644
--- a/balancer/xds/edsbalancer/util_test.go
+++ b/balancer/xds/edsbalancer/util_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  * Copyright 2019 gRPC authors.
  *
diff --git a/balancer/xds/xds.go b/balancer/xds/xds.go
index 6a8488b97..1097920b8 100644
--- a/balancer/xds/xds.go
+++ b/balancer/xds/xds.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  *
  * Copyright 2019 gRPC authors.
diff --git a/balancer/xds/xds_client.go b/balancer/xds/xds_client.go
index d18d9033a..181bc3827 100644
--- a/balancer/xds/xds_client.go
+++ b/balancer/xds/xds_client.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  *
  * Copyright 2019 gRPC authors.
diff --git a/balancer/xds/xds_client_test.go b/balancer/xds/xds_client_test.go
index 942f6ae07..409ee099a 100644
--- a/balancer/xds/xds_client_test.go
+++ b/balancer/xds/xds_client_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  *
  * Copyright 2019 gRPC authors.
diff --git a/balancer/xds/xds_test.go b/balancer/xds/xds_test.go
index 21a9fe2e4..c175f086b 100644
--- a/balancer/xds/xds_test.go
+++ b/balancer/xds/xds_test.go
@@ -1,3 +1,5 @@
+// +build go1.12
+
 /*
  *
  * Copyright 2019 gRPC authors.