```
interface A {
fun <T> foo(): T
}
class B(val a: A) : A by A {
generated fun <T'> foo(): T' {
return a.foo() // <------
}
}
```
There was a problem that type of generated delegated call used
an unsubstituted type of the original delegated declaration, which led
to a situation when (see example) type of call `a.foo()` was not `T'`
but `T`, which led to incorrect IR and further exceptions on backend
^KT-64257 Fixed
^KT-64284 Obsolete
vladislav.grechko