diff --git a/docker-compose.yml b/docker-compose.yml
index 50c188e56f53..a9fa22ad9c83 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -180,8 +180,9 @@ services:
       - linux-x64x11-xenial
 
   linux-x64x11-clang-3-9-prebuilt:
-    <<: *common-definitions
-    <<: *build-volumes
+    <<: 
+      - *common-definitions
+      - *build-volumes
     image: gcr.io/cobalt-tools/build-cobalt-linux-x64x11-clang-3-9:1.4
     environment:
       <<: *shared-build-env