diff --git a/core/Makefile b/core/Makefile
index bff9ec0..452b2c9 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -26,7 +26,8 @@
     $(eval _src := $(call word-colon,1,$(cf))) \
     $(eval _dest := $(call word-colon,2,$(cf))) \
     $(call check-product-copy-files,$(cf)) \
-    $(if $(filter $(unique_product_copy_files_destinations),$(_dest)),, \
+    $(if $(filter $(unique_product_copy_files_destinations),$(_dest)), \
+        $(info PRODUCT_COPY_FILES $(cf) ignored.), \
         $(eval _fulldest := $(call append-path,$(PRODUCT_OUT),$(_dest))) \
         $(eval $(call copy-one-file,$(_src),$(_fulldest))) \
         $(eval ALL_DEFAULT_INSTALLED_MODULES += $(_fulldest)) \