JSTests/stress/create-promise-finalize.js - external/github.com/WebKit/webkit - Git at Google

 function foo() {
     class P extends Promise {}
     new P(()=>{});
 }

 foo();
 drainMicrotasks();
 gc();
 foo();
	function foo() {
	class P extends Promise {}
	new P(()=>{});
	}

	foo();
	drainMicrotasks();
	gc();
	foo();