Unable to rename parameter properties

Rename `parent` to `parent_`.

``` ts
class Foo {
  constructor(private parent) {
    parent
  }
}
```

expected

``` ts
class Foo {
  constructor(private parent_) {
    parent_
  }
}
```

actual

``` ts
class Foo {
  constructor(private parent_) {
    parent
  }
}
```

Visual Studio 2013
