Overloading parent method

Why i can't do something like this:

``` js
/** @constructor */
function Foo() {}

/**
* @param {string} a
* @return {string}
*/
Foo.prototype.get = function (a) { return ''; }

/**
* @constructor
* @extends {Foo}
*/
function Foo2() {}

/**
* @override
* @param {number} b
*/
Foo2.prototype.get = function (a, b) { return ''; }
```

---

Warning: JSC_HIDDEN_SUPERCLASS_PROPERTY_MISMATCH: mismatch of the get property type and the type of the property it overrides from superclass Foo.

---

I think it's strange behavior. Also, i can't override parent parameters.

``` js
/** @constructor */
function Foo() {}

/**
* @param {string} a
* @return {string}
*/
Foo.prototype.get = function (a) { return ''; }

/**
* @constructor
* @extends {Foo}
*/
function Foo2() {}

/**
* @override
* @param {number} a
*/
Foo2.prototype.get = function (a) { return ''; }
```