diff --git a/src/core/parser.js b/src/core/parser.js
index 7b59765c3..48a615de9 100644
--- a/src/core/parser.js
+++ b/src/core/parser.js
@@ -528,6 +528,7 @@ var Parser = (function ParserClosure() {
     },
     makeFilter: function Parser_makeFilter(stream, name, maybeLength, params) {
       if (stream.dict.get('Length') === 0 && !maybeLength) {
+        warn('Empty "' + name + '" stream.');
         return new NullStream(stream);
       }
       try {