gistfile1.txt

--- a/src/gc/collector.cpp
+++ b/src/gc/collector.cpp
@@ -231,12 +231,16 @@ void GCVisitor::visit(void* p) {
     if (!p)
         return;
 
-    if (isNonheapRoot(p)) {
-        return;
-    } else {
-        ASSERT(global_heap.getAllocationFromInteriorPointer(p)->user_data == p, "%p", p);
+    GCAllocation* alloc = global_heap.getAllocationFromInteriorPointer(p);
+    if (alloc) {
+        ASSERT(alloc->user_data == p, "%p", p);
         stack->push(p);
     }
+#ifndef NDEBUG
+    else {
+        ASSERT(isNonheapRoot(p), "%p", p);
+    }
+#endif
 }