Maybe in the future we could remove type from the
KtImplicitReceiverValue, because it has ktSymbol, and in theory
that should be enough to create corresponding KtType.
Unfortunately that is not the case for KtClassOrObjectSymbol --
it doesn't have the API for "default" type creation currently.
Regarding code in KtFirCallResolver.kt -- it seems like code there
needs some love in the future. Psi created via custom code there,
because for call x() FIR has receiver x with psi = null
Use-site substitution override happens in situations like this:
```
interface List<A> { fun get(i: Int): A }
fun take(list: List<String>) {
list.get(10) // this call
}
```
We want to have those overrides unwrapped, because we don't want
to deal with a different KtSymbol for each possible use-site
^KT-50862 Fixed
Jinseong Jeon