--- a/js/src/jsgcinlines.h
+++ b/js/src/jsgcinlines.h
@@ -190,17 +190,17 @@ class ZoneCellIterImpl
 {
     ArenaIter arenaIter;
     ArenaCellIterImpl cellIter;
 
   public:
     ZoneCellIterImpl(JS::Zone* zone, AllocKind kind) {
         JSRuntime* rt = zone->runtimeFromAnyThread();
         MOZ_ASSERT(zone);
-        MOZ_ASSERT(rt->gc.nursery.isEmpty());
+        MOZ_ASSERT_IF(IsNurseryAllocable(kind), rt->gc.nursery.isEmpty());
 
         // We have a single-threaded runtime, so there's no need to protect
         // against other threads iterating or allocating. However, we do have
         // background finalization; we may have to wait for this to finish if
         // it's currently active.
         if (IsBackgroundFinalized(kind) && zone->arenas.needBackgroundFinalizeWait(kind))
             rt->gc.waitBackgroundSweepEnd();
 
@@ -251,18 +251,20 @@ class ZoneCellIter
     JS::AutoAssertNoAlloc noAlloc;
 
   public:
     ZoneCellIter(JS::Zone* zone, AllocKind kind) {
         // If called from outside a GC, ensure that the heap is in a state
         // that allows us to iterate.
         JSRuntime* rt = zone->runtimeFromMainThread();
         if (!rt->isHeapBusy()) {
-            // Evict the nursery before iterating so we can see all things.
-            rt->gc.evictNursery();
+            // If we are iterating a nursery-allocated kind then we need to
+            // evict first so that we can see all things.
+            if (IsNurseryAllocable(kind))
+                rt->gc.evictNursery();
 
             // Assert that no GCs can occur while a ZoneCellIter is live.
             noAlloc.disallowAlloc(rt);
         }
 
         impl.emplace(zone, kind);
     }