diff --git a/toolkit/components/places/nsPlacesAutoComplete.js b/toolkit/components/places/nsPlacesAutoComplete.js
index c6d709833b8a..ab8f9dda2f86 100644
--- a/toolkit/components/places/nsPlacesAutoComplete.js
+++ b/toolkit/components/places/nsPlacesAutoComplete.js
@@ -624,7 +624,7 @@ nsPlacesAutoComplete.prototype = {
   handleResult: function PAC_handleResult(aResultSet)
   {
     let row, haveMatches = false;
-    while (row = aResultSet.getNextRow()) {
+    while ((row = aResultSet.getNextRow())) {
       let match = this._processRow(row);
       haveMatches = haveMatches || match;
 
diff --git a/toolkit/components/places/nsPlacesExpiration.js b/toolkit/components/places/nsPlacesExpiration.js
index 46d4c4195e7f..f987704ac352 100644
--- a/toolkit/components/places/nsPlacesExpiration.js
+++ b/toolkit/components/places/nsPlacesExpiration.js
@@ -619,7 +619,7 @@ nsPlacesExpiration.prototype = {
       return;
 
     let row;
-    while (row = aResultSet.getNextRow()) {
+    while ((row = aResultSet.getNextRow())) {
       if (!("_expectedResultsCount" in this))
         this._expectedResultsCount = row.getResultByName("expected_results");
       if (this._expectedResultsCount > 0)