diff --git a/src/core/stream.js b/src/core/stream.js
index 0b5d5e1f6..03c827d82 100644
--- a/src/core/stream.js
+++ b/src/core/stream.js
@@ -167,6 +167,11 @@ var DecodeStream = (function DecodeStreamClosure() {
   }
 
   DecodeStream.prototype = {
+    // eslint-disable-next-line getter-return
+    get length() {
+      unreachable("Should not access DecodeStream.length");
+    },
+
     get isEmpty() {
       while (!this.eof && this.bufferLength === 0) {
         this.readBlock();