diff --git a/js/src/jit/MacroAssembler.cpp b/js/src/jit/MacroAssembler.cpp
index 6c7d1991633c..ba529757ebb2 100644
--- a/js/src/jit/MacroAssembler.cpp
+++ b/js/src/jit/MacroAssembler.cpp
@@ -1173,7 +1173,7 @@ MacroAssembler::initGCThing(Register obj, Register temp, JSObject* templateObj,
 void
 MacroAssembler::initUnboxedObjectContents(Register object, UnboxedPlainObject* templateObject)
 {
-    const UnboxedLayout& layout = templateObject->layout();
+    const UnboxedLayout& layout = templateObject->layoutDontCheckGeneration();
 
     // Initialize reference fields of the object, per UnboxedPlainObject::create.
     if (const int32_t* list = layout.traceList()) {