Some type usage is detected as unused

[junmo-kim]

• Type used as generic type parameter

class AClass {
    ...
}

class BClass<T> {
    var t: T?
}

class CClass: BClass<AClass> {
    ...
}

-> AClass is detected as unused class.

• Only parameter is trailing closure

class DClass {
    init(closure: () -> Void)
}

...
DClass { doSomething() }
...

-> DClass is detected as unused class.