diff --git a/js/src/vm/GeneratorObject.cpp b/js/src/vm/GeneratorObject.cpp
index 082e382663..f0718c0f86 100644
--- a/js/src/vm/GeneratorObject.cpp
+++ b/js/src/vm/GeneratorObject.cpp
@@ -179,6 +179,8 @@ GeneratorObject::resume(JSContext* cx, InterpreterActivation& activation,
 {
     Rooted<GeneratorObject*> genObj(cx, &obj->as<GeneratorObject>());
     MOZ_ASSERT(genObj->isSuspended());
+    // See comment in InterpreterStack::resumeGeneratorCallFrame
+    MOZ_ASSERT_IF(genObj->isConstructing(), genObj->is<LegacyGeneratorObject>());
 
     RootedFunction callee(cx, &genObj->callee());
     RootedValue newTarget(cx, genObj->newTarget());
diff --git a/js/src/vm/Stack-inl.h b/js/src/vm/Stack-inl.h
index 9114a6a79e..5f66159c2c 100644
--- a/js/src/vm/Stack-inl.h
+++ b/js/src/vm/Stack-inl.h
@@ -351,7 +351,10 @@ InterpreterStack::resumeGeneratorCallFrame(JSContext* cx, InterpreterRegs& regs,
         constructing = MaybeConstruct(newTarget.isObject());
         MOZ_ASSERT_IF(constructing, callee->isConstructor());
     } else {
-        MOZ_ASSERT(!callee->isConstructor());
+        // We should really be doing MOZ_ASSERT(!callee->isConstructor()) here.
+        // However, the GeneratorObject only stores the callee as-is, which in the case of a lambda generator
+        // (i.e. a |new GeneratorFunction(...)| or derieved generator class) is still flagged as a constructor.
+        // Instead, we check for the correct state in GeneratorObject::resume.
     }
 
     // Include callee, |this|, and maybe |new.target|