diff --git a/mozilla/js/src/jsscan.c b/mozilla/js/src/jsscan.c
index 297797449d6..257c3532a0d 100644
--- a/mozilla/js/src/jsscan.c
+++ b/mozilla/js/src/jsscan.c
@@ -1012,6 +1012,7 @@ js_PeekTokenSameLine(JSContext *cx, JSTokenStream *ts)
     JSTokenType tt;
 
     JS_ASSERT(ts->lookahead == 0 ||
+              (ts->flags & TSF_ERROR) ||
               ON_CURRENT_LINE(ts, CURRENT_TOKEN(ts).pos) ||
               ts->tokens[(ts->cursor + ts->lookahead) & NTOKENS_MASK].type
                   == TOK_EOL);