--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -4149,22 +4149,22 @@ AutoGCSlice::AutoGCSlice(JSRuntime *rt)
         } else {
             JS_ASSERT(!c->needsBarrier());
         }
     }
 }
 
 AutoGCSlice::~AutoGCSlice()
 {
-    for (GCCompartmentsIter c(runtime); !c.done(); c.next()) {
+    /* We can't use GCCompartmentsIter if this is the end of the last slice. */
+    for (CompartmentsIter c(runtime); !c.done(); c.next()) {
         if (c->isGCMarking()) {
             c->setNeedsBarrier(true, JSCompartment::UpdateIon);
             c->arenas.prepareForIncrementalGC(runtime);
         } else {
-            JS_ASSERT(c->isGCSweeping());
             c->setNeedsBarrier(false, JSCompartment::UpdateIon);
         }
     }
 }
 
 static void
 PushZealSelectedObjects(JSRuntime *rt)
 {