我將set age()和屬性age:null設置為同名，結果報錯：Maximum call stack size exceeded，只要改成不同名就ok，請問這是什么原因？

var?man?=?{
?????	name:"nrt",
?????	sex:"female",
?????	age:null,
?????	get?age(){
?????		if(this.age?==?undefined)
?????		{
?????			return?new?Date().getFullYear()?-?1995;
?????		}
?????		else
?????		{
?????			return?this.age;
?????		}
?????		
?????	},
		set?age(val){
	?????		val?=?+val?//轉換為數值類型
	?????		if(!isNaN(val)?&&?val?>?0?&&?val?<?150)
	?????		{
	?????			this.age?=?+val;
	?????		}
	?????		else
	?????		{
	?????			console.log("輸入非法");
	?????		}
	?????	}
?????}

?????console.log(man.age);
?????man.age?=?30;
?????console.log(man.age);