diff --git a/core/base_rules.mk b/core/base_rules.mk
index 6f4b826..97bcbaa 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -73,6 +73,28 @@
   ifeq ($(filter $(GRANDFATHERED_USER_MODULES),$(LOCAL_MODULE)),)
     $(warning *** Module name: $(LOCAL_MODULE))
     $(warning *** Makefile location: $(LOCAL_PATH))
+    $(warning * )
+    $(warning * Each module must use a LOCAL_MODULE_TAGS in its)
+    $(warning * Android.mk. Possible tags declared by a module:)
+    $(warning * )
+    $(warning *     optional, debug, eng, tests, samples)
+    $(warning * )
+    $(warning * If the module is expected to be in all builds)
+    $(warning * of a product, then it should use the)
+    $(warning * "optional" tag: )
+    $(warning * )
+    $(warning *    Add "LOCAL_MODULE_TAGS := optional" in the)
+    $(warning *    Android.mk for the affected module, and add)
+    $(warning *    the LOCAL_MODULE value for that component)
+    $(warning *    into the PRODUCT_PACKAGES section of product)
+    $(warning *    makefile(s) where it's necessary, if)
+    $(warning *    appropriate.)
+    $(warning * )
+    $(warning * If the component should be in EVERY build of ALL)
+    $(warning * products, then add its LOCAL_MODULE value to the)
+    $(warning * PRODUCT_PACKAGES section of)
+    $(warning * build/target/product/core.mk)
+    $(warning * )
     $(error user tag detected on new module - user tags are only supported on legacy modules)
   endif
 endif