Overrided interface properties does not inherit type information

I have followed code:

``` js
/**
* @interface
*/
var Itf = function(){};

/** @type {boolean} */
Itf.prototype.prop;

/**
* @constructor
* @implements {Itf}
*/
var Cls = function(){}

/** @override */
Cls.prototype.prop;
```

Compiling it with "--compilation_level ADVANCED_OPTIMIZATIONS --jscomp_warning reportUnknownTypes --warning_level VERBOSE" I get a warning:

```
test.js:17: WARNING - could not determine the type of this expression
Cls.prototype.prop;
^
```

If I add `@type {boolean}` to `Cls.prototype.prop` all is fine.
It seems compiler is unable to infer type from `Itf.prototype.prop`.

Initializing overrided property resolves a problem, but in my case it should be uninitialized (it's type actually `{(boolean|undefined)}`).

See discussion: https://groups.google.com/forum/#!topic/closure-compiler-discuss/gdKj25kAWeg