--- a/layout/generic/nsBlockFrame.h
+++ b/layout/generic/nsBlockFrame.h
@@ -475,27 +475,27 @@ public:
    *
    * @returns true, if any of the floats at the beginning of our mFloats list
    *          have the NS_FRAME_IS_PUSHED_FLOAT bit set; false otherwise.
    */
   bool HasPushedFloatsFromPrevContinuation() const {
     if (!mFloats.IsEmpty()) {
       // If we have pushed floats, then they should be at the beginning of our
       // float list.
-      if (mFloats.FrameAt(0)->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT) {
+      if (mFloats.FirstChild()->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT) {
         return true;
       }
     }
 
 #ifdef DEBUG
     // Double-check the above assertion that pushed floats should be at the
     // beginning of our floats list.
-    for (int32_t i = 0; i < mFloats.GetLength(); i++) {
-      NS_ASSERTION(!(mFloats.FrameAt(i)->GetStateBits() &
-        NS_FRAME_IS_PUSHED_FLOAT),
+    for (nsFrameList::Enumerator e(mFloats); !e.AtEnd(); e.Next()) {
+      nsIFrame* f = e.get();
+      NS_ASSERTION(!(f->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT),
         "pushed floats must be at the beginning of the float list");
     }
 #endif
     return false;
   }
 
 protected: